ABC problem

From Rosetta Code


Task
ABC problem
You are encouraged to solve this task according to the task description, using any language you may know.

You are given a collection of ABC blocks   (maybe like the ones you had when you were a kid).

There are twenty blocks with two letters on each block.

A complete alphabet is guaranteed amongst all sides of the blocks.

The sample collection of blocks:

 (B O)
 (X K)
 (D Q)
 (C P)
 (N A)
 (G T)
 (R E)
 (T G)
 (Q D)
 (F S)
 (J W)
 (H U)
 (V I)
 (A N)
 (O B)
 (E R)
 (F S)
 (L Y)
 (P C)
 (Z M)


Task

Write a function that takes a string (word) and determines whether the word can be spelled with the given collection of blocks.


The rules are simple:

  1.   Once a letter on a block is used that block cannot be used again
  2.   The function should be case-insensitive
  3.   Show the output on this page for the following 7 words in the following example


Example
    >>> can_make_word("A")
    True
    >>> can_make_word("BARK")
    True
    >>> can_make_word("BOOK")
    False
    >>> can_make_word("TREAT")
    True
    >>> can_make_word("COMMON")
    False
    >>> can_make_word("SQUAD")
    True
    >>> can_make_word("CONFUSE")
    True
Other tasks related to string operations:
Metrics
Counting
Remove/replace
Anagrams/Derangements/shuffling
Find/Search/Determine
Formatting
Song lyrics/poems/Mad Libs/phrases
Tokenize
Sequences



11l[edit]

Translation of: Python
F can_make_word(word)
   I word == ‘’
      R 0B

   V blocks_remaining = ‘BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM’.split(‘ ’)

   L(ch) word.uppercase()
      L(block) blocks_remaining
         I ch C block
            blocks_remaining.remove(block)
            L.break
      L.was_no_break
         R 0B
   R 1B

print([‘’, ‘a’, ‘baRk’, ‘booK’, ‘treat’, ‘COMMON’, ‘squad’, ‘Confused’].map(w -> ‘'’w‘': ’can_make_word(w)).join(‘, ’))

360 Assembly[edit]

The program uses one ASSIST macro (XPRNT) to keep the code as short as possible.

*        ABC Problem               21/07/2016
ABC      CSECT
         USING  ABC,R13            base register
         B      72(R15)            skip savearea
         DC     17F'0'             savearea
         STM    R14,R12,12(R13)    prolog
         ST     R13,4(R15)         " <-
         ST     R15,8(R13)         " ->
         LR     R13,R15            " addressability
         LA     R8,1               l=1
LOOPL    C      R8,=A(NN)          do l=1 to hbound(words)
         BH     ELOOPL
         LR     R1,R8              l
         MH     R1,=H'20'          *20
         LA     R10,WORDS-20(R1)   @words(l)
         MVC    STATUS,=CL5'true'  cflag='true'
         MVC    TBLOCKS,BLOCKS     tblocks=blocks
         MVC    CC(1),0(R10)       cc=substr(words(l),1,1)
         LA     R6,1               i=1
LOOPI    CLI    CC,C' '            do while cc<>' '
         BE     ELOOPI
         SR     R7,R7              k=0
         LH     R0,=H'1'           m=1
LOOPM    CH     R0,=AL2(L'TBLOCKS) do m=1 to length(tblocks)
         BH     ELOOPM
         LA     R5,TBLOCKS-1       @tblocks[0]
         AR     R5,R0              @tblocks[m]
         CLC    0(1,R5),CC         if substr(tblocks,m,1)=cc
         BNE    INDEXM
         LR     R7,R0              k=m=index(tblocks,cc)
         B      ELOOPM
INDEXM   AH     R0,=H'1'           m=m+1
         B      LOOPM
ELOOPM   LTR    R7,R7              if k=0
         BNZ    OKK
         MVC    STATUS,=CL5'false' cflag='false'
         B      EIFK0
OKK      LA     R4,TBLOCKS-2       @tblocks[-1]
         AR     R4,R7              +k
         CLI    0(R4),C'('         if substr(tblocks,k-1,1)='('
         BNE    SECOND
         LA     R0,1               j=1
         B      EIFBLOCK
SECOND   LA     R0,3               j=3
EIFBLOCK LR     R2,R7              k
         SR     R2,R0              k-j
         LA     R4,TBLOCKS-1       @tblocks[0]
         AR     R4,R2              @tblocks[k-j]
         MVC    0(5,R4),=CL5' '    substr(tblocks,k-j,5)='     '
EIFK0    LA     R6,1(R6)           i=i+1
         LR     R4,R10             @words
         AR     R4,R6              +i
         BCTR   R4,0               -1
         MVC    CC,0(R4)           cc=substr(words,i,1)
         B      LOOPI
ELOOPI   MVC    PG(20),0(R10)      tabword(l)
         MVC    PG+20(5),STATUS    status
         XPRNT  PG,80              print buffer
         LA     R8,1(R8)           l=l+1
         B      LOOPL
ELOOPL   L      R13,4(0,R13)       epilog 
         LM     R14,R12,12(R13)    " restore
         XR     R15,R15            " rc=0
         BR     R14                exit
WORDS    DC     CL20'A',CL20'BARK',CL20'BOOK',CL20'TREAT',CL20'COMMON'
         DC     CL20'SQUAD',CL20'CONFUSE'
BLOCKS   DS     0CL122
 DC CL61'((B O) (X K) (D Q) (C P) (N A) (G T) (R E) (T G) (Q D) (F S) '
 DC CL61'(J W) (H U) (V I) (A N) (O B) (E R) (F S) (L Y) (P C) (Z M)) '
TBLOCKS  DS     CL(L'BLOCKS)       work blocks
CC       DS     CL1                letter to find
STATUS   DS     CL5                true/false
PG       DC     CL80' '            buffer
         YREGS
NN       EQU    (BLOCKS-WORDS)/L'WORDS  number of words
         END    ABC
Output:
A                   true
BARK                true
BOOK                false
TREAT               true
COMMON              false
SQUAD               true
CONFUSE             true

8080 Assembly[edit]

		org	100h
		jmp	test
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Subroutine 'blocks': takes a $-terminated string in 
		;;; DE containing a word, and checks whether it can be 
		;;; written with the blocks.
		;;; Returns: carry flag set if word is accepted.
		;;; Uses registers: A, B, D, E, H, L
blocks:		push	d		; Store string pointer
		lxi	h,blockslist	; At the start, all blocks are
		lxi	d,blocksavail	; available
		mvi	b,40
blocksinit:	mov	a,m
		stax	d
		inx	h
		inx	d
		dcr	b
		jnz	blocksinit
		pop	d		; Restore string pointer
blockschar:	ldax	d		; Get current character
		cpi	'$'		; End of string?
		stc			; Set carry flag (accept string)
		rz			; And then we're done
		ani	0DFh		; Make uppercase
		lxi	h,blocksavail	; Is it available?
		mvi	b,40
blockscheck:	cmp	m
		jz	blocksaccept	; Yes, we found it
		inx	h		; Try next available char
		dcr	b
		jnz	blockscheck
		ana	a		; Char unavailable, clear
		ret			; carry and stop.
blocksaccept:	mvi	m,0		; We've now used this char
		mov	a,l		; And its blockmate
		xri	1
		mov	l,a
		mvi	m,0
		inx	d		; Try next char in string
		jmp	blockschar
		;; Note: 'blocksavail' must not cross page boundary
blockslist:	db	'BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM'
blocksavail:	ds	40
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Test code: run the subroutine on the given words.
test:		lxi	h,words
doword:		mov	e,m		; Get pointer to next word
		inx	h
		mov	d,m
		inx	h
		mov	a,e		; If zero, end of word list
		ora	d
		rz
		push	h		; Save pointer to list
		push	d		; Save pointer to word
		mvi	c,9		; Write word to console
		call	5
		pop	d		; Retrieve word ponter
		call	blocks		; Run the 'blocks' routine
		lxi	d,yes		; Say 'yes',
		jc	yesno		; if the carry is set.
		lxi	d,no		; Otherwise, say 'no'.
yesno:		mvi	c,9
		call	5
		pop	h		; Restore list pointer
		jmp	doword		; Do next word
yes:		db	': Yes',13,10,'$'
no:		db	': No',13,10,'$'
words:		dw	wrda,wrdbark,wrdbook,wrdtreat,wrdcommon
		dw	wrdsquad,wrdconfuse,0
wrda:		db	'A$'
wrdbark:	db	'BARK$'
wrdbook:	db	'BOOK$'
wrdtreat:	db	'TREAT$'
wrdcommon:	db	'COMMON$'
wrdsquad:	db	'SQUAD$'
wrdconfuse:	db	'CONFUSE$'
Output:
A>blocks
A: Yes
BARK: Yes
BOOK: No
TREAT: Yes
COMMON: No
SQUAD: Yes
CONFUSE: Yes

8086 Assembly[edit]

Translation of: 8080 Assembly
	cpu	8086
	bits	16
	org	100h
section	.text
	jmp	demo
	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	;;; Subroutine "blocks": see if the $-terminated string in DS:BX
	;;; can be written with the blocks.
	;;; Returns: carry flag set if word is accepted.
	;;; Uses registers: AL, BX, CX, SI, DI
	;;; Assumes CS=DS=ES
blocks:	mov	si,.list	; Set all blocks available
	mov	di,.avail
	mov	cx,20
	rep	movsw
.char:	mov 	al,[bx]		; Get current character
	inc	bx
	cmp	al,'$'		; Are we at the end?
	je	.ok		; Then the string is accepted
	mov	cx,40		; If not, check if block is available 
	mov	di,.avail
	repne	scasb
	test	cx,cx		; This clears the carry flag
	jz	.out		; If zero, block is not available
	dec	di		; Zero out the block we found
	mov	[di],ch		; CH is guaranteed 0 here
	xor	di,1		; Point at other character on block
	mov	[di],ch		; Zero out that one too.
	jmp	.char
.ok:	stc
.out:	ret
.list:	db	'BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM'
.avail:	db	'                                        '
	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	;;; Test code: run the subroutine on the given words
demo:	mov	bp,words
wrd:	mov	dx,[bp]		; Get word
	test	dx,dx		; End of words?
	jz	stop
	mov	ah,9		; Print word
	int	21h
	mov	bx,dx		; Run subroutine
	call	blocks
	mov	dx,yes		; Print yes or no depending on carry
	jc	print
	mov	dx,no
print:	mov	ah,9
	int	21h
	inc	bp
	inc	bp
	jmp	wrd
stop:	ret
section	.data
yes:	db	': Yes',13,10,'$'
no:	db	': No',13,10,'$'
words:	dw	.a,.bark,.book,.treat,.cmn,.squad,.confs,0
.a:	db	'A$'
.bark:	db	'BARK$'
.book:	db	'BOOK$'
.treat:	db	'TREAT$'
.cmn:	db	'COMMON$'
.squad:	db	'SQUAD$'
.confs:	db	'CONFUSE$'
Output:
A: Yes
BARK: Yes
BOOK: No
TREAT: Yes
COMMON: No
SQUAD: Yes
CONFUSE: Yes

8th[edit]

\ ========================================================================================
\ You are given a collection of ABC blocks
\ There are twenty blocks with two letters on each block.
\ A complete alphabet is guaranteed amongst all sides of the blocks.
\ 
\ Write a function that takes a string (word) and determines whether 
\ the word can be spelled with the given collection of blocks.
\
\ Rules:
\ 1. Once a letter on a block is used that block cannot be used again
\ 2. The function should be case-insensitive
\ 3. Show the output on this page for the following 7 words in the following example
\    can_make_word(???) where ??? is resp.:
\        "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"
\
\ NOTE:
\ to make the program readable for even n00bs, I have a comment at the end of each line.
\ The comments take the form of:
\                    \ <stack> | <rstack>
\ in order to be able to follow exactly what the program does.
\ ========================================================================================

["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS","JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"] var, blks
["a", "AbBa", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"] var, chkwrds

needs stack/rstack

a:new var, paths \ Keeps the combinatory explosion of letter paths
var wrd
var success
var ix

: uni2char "" swap s:+ ;
  
: char2uni 0 s:@ nip ;

: rreset rstack st:clear drop ;

: addoneletter \ ix path --                   \ ix path | letter
  r@                                          \ ix path letter | letter
  s:+                                         \ ix newpath | letter
  paths @                                     \ ix newpath paths | letter
  -rot                                        \ paths ix newval | letter
  a:!                                         \ paths | letter
  drop                                        \ | letter
  ;

: oneletter \ letter --                       \ letter
  >r                                          \ | letter
  paths @ ' addoneletter a:each drop          \ | letter
  ;

: addtwoletters \ ix path --                  \ ix path | letter1 letter2 halflen
  swap                                        \ path ix | letter1 letter2 halflen
  dup                                         \ path ix ix | letter1 letter2 halflen 
  r@                                          \ path ix ix halflen | letter1 letter2 halflen
  n:<                                         \ path ix bool | letter1 letter2 halflen 
  if                                          \ path ix | letter1 letter2 halflen 
    swap                                      \ ix path | letter1 letter2 halflen 
    1 rpick                                   \ ix path letter | letter1 letter2 halflen 
  else
    swap                                      \ ix path | letter1 letter2 halflen 
    2 rpick                                   \ ix path letter | letter1 letter2 halflen 
  then
  s:+                                         \ ix newpath | letter1 letter2 halflen
  paths @                                     \ ix newpath paths | letter1 letter2 halflen 
  -rot                                        \ paths ix newpath | letter1 letter2 halflen 
  a:!                                         \ paths | letter1 letter2 halflen
  drop                                        \ | letter1 letter2 halflen
  ;
  
: twoletters \ letters --                     \ letters
  \ fetch the 2 letters
  dup                                         \ letters letters
  1 s:lsub                                    \ letters letter1
  >r                                          \ letters | letter1
  1 s:rsub                                    \ letter2 | letter1
  >r                                          \ | letter1 letter2
  \ duplicate paths in itself
  paths @ dup a:+                             \ paths | letter1 letter2
  \ halfway length of array
  a:len                                       \ paths len | letter1 letter2
  2 /                                         \ paths halflen | letter1 letter2
  >r                                          \ paths | letter1 letter2 halflen
  \ add letters to paths
  ' addtwoletters a:each drop                 \ | letter1 letter2 halflen
  rreset                                      \  
  ;

: chkletter \ letter -- letter                \ letter
  dup                                         \ letter letter
  wrd @                                       \ letter letter word
  swap uni2char                               \ letter word letter
  s:search                                    \ letter word index
  null?                                       \ letter word index bool
  nip                                         \ letter word bool
  if                                          \ letter word
    2drop                                     \
    ""                                        \ letter
  else                                        \ letter word
    drop                                      \ letter
  then                                        \
  ;

: buildpaths \ ix blk --                      \ ix blk
  nip                                         \ blk
  ' chkletter s:map                           \ resultletters
  s:len                                       \ resultletters len
  dup                                         \ resultletters len len
  0                                           \ resultletters len len 0
  n:=                                         \ resultletters len bool
  if                                          \ resultletters len
    \ This block contains no letters of current word
    2drop                                     \ 
    ;;                                        \ exit word
  then                                        \ resultletters len
  1                                           \ resultletters len 1
  n:=                                         \ resultletters bool
  if                                          \ resultletters
    oneletter                                 \
  else                                        \ resultletters
    twoletters                                \
  then 
  ;

: chkokpath \ ix wrdch --                     \ ix wrdch | path
  swap                                        \ wrdch ix | path
  ix !                                        \ wrdch | path
  r@                                          \ wrdch path | path
  dup                                         \ wrdch path path | path
  ""                                          \ wrdch path path "" | path
  s:=                                         \ wrdch path bool | path
  if                                          \ wrdch path | path                                          
    \ Path is empty - no match
    2drop                                     \ | path
    break                                     \ | path
    ;;                                        \ | path
  then
  swap                                        \ path wrdch | path
  uni2char                                    \ path wrdch | path
  s:search                                    \ path pos | path
  null?                                       \ path pos bool | path
  if                                          \ path pos | path
    \ Letter not found in path - no match
    2drop                                     \ | path
    break                                     \ | path
  else                                        \ path pos | path
    wrd @                                     \ path pos wrd | path
    s:len                                     \ path pos wrd len | path
    nip                                       \ path pos len | path
    n:1-                                      \ path pos cix | path
    ix @                                      \ path pos cix ix | path
    n:=                                       \ path pos bool | path
    if                                        \ path pos | path 
      \ We have a match!
      true success !                          \ path pos | path
      2drop                                   \ | path 
      break                                   \ | path
    else                                      \ path pos | path
      1                                       \ path pos len | path
      s:-                                     \ restpath | path
      rdrop >r                                \ | restpath
    then
  then 
  ;

: chkpath \ ix path --                        \ ix path
  nip                                         \ path
  >r                                          \ | path
  wrd @                                       \ wrd | path
  ' chkokpath s:each                          \ | path
  rdrop                                       \
  success @                                   \ success
	if                                          \ 
	  break                                     \
  then
  ;
  
: chkwrd \ ix wrd --                          \ ix wrd
  nip                                         \ wrd
  s:uc                                        \ wrdupper
  "Word=" . dup .                             \ wrdupper 
  wrd !                                       \  
  \ other word - clear paths
  paths @ a:clear "" a:push drop              \ 
  \ create path tree for this word
  blks @ ' buildpaths a:each drop             \
  \ check if word can be made from a path
  false success !                             \   
  paths @ ' chkpath a:each drop               \
  success @                                   \ success
  "\t\t" . . cr                               \
  ;

: app:main
  chkwrds @ ' chkwrd a:each drop              \ check if word can be made
  bye
  ;

AArch64 Assembly[edit]

Works with: as version Raspberry Pi 3B version Buster 64 bits
/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program problemABC64.s   */ 

/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ TRUE, 1
.equ FALSE, 0

/*********************************/
/* Initialized data              */
/*********************************/
.data
szMessTitre1:        .asciz "Can_make_word: @ \n"
szMessTrue:          .asciz "True.\n"
szMessFalse:         .asciz "False.\n"
szCarriageReturn:    .asciz "\n"

szTablBloc:          .asciz "BO"
                     .asciz "XK"
                     .asciz "DQ"
                     .asciz "CP"
                     .asciz "NA"
                     .asciz "GT"
                     .asciz "RE"
                     .asciz "TG"
                     .asciz "QD"
                     .asciz "FS"
                     .asciz "JW"
                     .asciz "HU"
                     .asciz "VI"
                     .asciz "AN"
                     .asciz "OB"
                     .asciz "ER"
                     .asciz "FS"
                     .asciz "LY"
                     .asciz "PC"
                     .asciz "ZM"
                     .equ NBBLOC, (. -  szTablBloc) / 3
                     
szWord1:             .asciz "A"
szWord2:             .asciz "BARK"
szWord3:             .asciz "BOOK"
szWord4:             .asciz "TREAT"
szWord5:             .asciz "COMMON"
szWord6:             .asciz "SQUAD"
szWord7:             .asciz "CONFUSE"
/*********************************/
/* UnInitialized data            */
/*********************************/
.bss
.align 4
qtabTopBloc:         .skip 8 * NBBLOC
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main 
main:                                // entry of program 
    ldr x0,qAdrszWord1
    bl traitBlock                    // control word

    ldr x0,qAdrszWord2
    bl traitBlock                    // control word
    
    ldr x0,qAdrszWord3
    bl traitBlock                    // control word
    
    ldr x0,qAdrszWord4
    bl traitBlock                    // control word
        
    ldr x0,qAdrszWord5
    bl traitBlock                    // control word
        
    ldr x0,qAdrszWord6
    bl traitBlock                    // control word
        
    ldr x0,qAdrszWord7
    bl traitBlock                    // control word

100:                                  // standard end of the program 
    mov x0, #0                        // return code
    mov x8, #EXIT                     // request to exit program
    svc #0                            // perform the system call
 
qAdrszCarriageReturn:     .quad szCarriageReturn
qAdrszWord1:              .quad szWord1
qAdrszWord2:              .quad szWord2
qAdrszWord3:              .quad szWord3
qAdrszWord4:              .quad szWord4
qAdrszWord5:              .quad szWord5
qAdrszWord6:              .quad szWord6
qAdrszWord7:              .quad szWord7
/******************************************************************/
/*          traitement                                           */ 
/******************************************************************/
/* x0 contains word */
traitBlock:
    stp x1,lr,[sp,-16]!       // save  registres
    mov x1,x0
    ldr x0,qAdrszMessTitre1   // insertion word in message
    bl strInsertAtCharInc
    bl affichageMess          // display title message
    mov x0,x1
    bl controlBlock           // control 
    cmp x0,#TRUE              // ok ?
    bne 1f
    ldr x0,qAdrszMessTrue     // yes
    bl affichageMess
    b 100f
1:                            // no
    ldr x0,qAdrszMessFalse
    bl affichageMess
100:
    ldp x1,lr,[sp],16         // restaur des  2 registres
    ret
qAdrszMessTitre1:         .quad szMessTitre1
qAdrszMessFalse:          .quad szMessFalse
qAdrszMessTrue:           .quad szMessTrue
/******************************************************************/
/*        control if letters are in block                       */ 
/******************************************************************/
/* x0 contains word */
controlBlock:
    stp x1,lr,[sp,-16]!          // save  registres
    stp x2,x3,[sp,-16]!          // save  registres
    stp x4,x5,[sp,-16]!          // save  registres
    stp x6,x7,[sp,-16]!          // save  registres
    stp x8,x9,[sp,-16]!          // save  registres
    mov x5,x0              // save word address
    ldr x4,qAdrqtabTopBloc
    ldr x6,qAdrszTablBloc
    mov x2,#0
    mov x3,#0
1:                          // init table top block used
    str x3,[x4,x2,lsl #3]
    add x2,x2,#1
    cmp x2,#NBBLOC
    blt 1b
    mov x2,#0
2:                          // loop to load letters 
    ldrb w3,[x5,x2]
    cbz w3,10f              // end
    mov x0,0xDF
    and x3,x3,x0         // transform in capital letter
    mov x8,#0
3:                          // begin loop control block
    ldr x7,[x4,x8,lsl #3]   // block already used ?
    cbnz x7,5f              // yes
    add x9,x8,x8,lsl #1     // no -> index * 3
    ldrb w7,[x6,x9]         // first block letter
    cmp w3,w7               // equal ?
    beq 4f
    add x9,x9,#1
    ldrb w7,[x6,x9]         // second block letter
    cmp w3,w7               // equal ?
    beq 4f
    b 5f
4:
    mov x7,#1               // top block
    str x7,[x4,x8,lsl #3]   // block used
    add x2,x2,#1
    b 2b                    // next letter
5:
    add x8,x8,#1
    cmp x8,#NBBLOC
    blt 3b
    mov x0,#FALSE           // no letter find on block -> false
    b 100f 
10:                         // all letters are ok
    mov x0,#TRUE
100:
    ldp x8,x9,[sp],16       // restaur des  2 registres
    ldp x6,x7,[sp],16       // restaur des  2 registres
    ldp x4,x5,[sp],16       // restaur des  2 registres
    ldp x2,x3,[sp],16       // restaur des  2 registres
    ldp x1,lr,[sp],16       // restaur des  2 registres
    ret
qAdrqtabTopBloc:   .quad qtabTopBloc
qAdrszTablBloc:    .quad szTablBloc
/********************************************************/
/*        File Include fonctions                        */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"
Output:
Can_make_word: A
True.
Can_make_word: BARK
True.
Can_make_word: BOOK
False.
Can_make_word: TREAT
True.
Can_make_word: COMMON
False.
Can_make_word: SQUAD
True.
Can_make_word: CONFUSE
True.

ABAP[edit]

REPORT z_rosetta_abc.

" Type declaration for blocks of letters
TYPES: BEGIN OF block,
         s1 TYPE char1,
         s2 TYPE char1,
       END OF block,

       blocks_table TYPE STANDARD TABLE OF block.

DATA: blocks TYPE blocks_table.

CLASS word_maker DEFINITION.
  PUBLIC SECTION.
    CLASS-METHODS:
      can_make_word
        IMPORTING word          TYPE string
                  letter_blocks TYPE blocks_table
        RETURNING VALUE(found)  TYPE abap_bool.
ENDCLASS.

CLASS word_maker IMPLEMENTATION.
  METHOD can_make_word.

    " Create a reader stream that reads 1 character at a time
    DATA(reader) = NEW cl_abap_string_c_reader( word ).

    DATA(blocks) = letter_blocks.

    WHILE reader->data_available( ).

      DATA(ch) = to_upper( reader->read( 1 ) ).
      found = abap_false.

      LOOP AT blocks REFERENCE INTO DATA(b).
        IF ch = b->s1 OR ch = b->s2.
          found = abap_true.
          DELETE blocks INDEX sy-tabix.
          EXIT. " the inner loop once a character is found
        ENDIF.
      ENDLOOP.

      " If a character could not be found, stop looking further
      IF found = abap_false.
        RETURN.
      ENDIF.
    ENDWHILE.

  ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.

  blocks = VALUE #( ( s1 = 'B' s2 = 'O' ) ( s1 = 'X' s2 = 'K' )
                    ( s1 = 'D' s2 = 'Q' ) ( s1 = 'C' s2 = 'P' )
                    ( s1 = 'N' s2 = 'A' ) ( s1 = 'G' s2 = 'T' )
                    ( s1 = 'R' s2 = 'E' ) ( s1 = 'T' s2 = 'G' )
                    ( s1 = 'Q' s2 = 'D' ) ( s1 = 'F' s2 = 'S' )
                    ( s1 = 'J' s2 = 'W' ) ( s1 = 'H' s2 = 'U' )
                    ( s1 = 'V' s2 = 'I' ) ( s1 = 'A' s2 = 'N' )
                    ( s1 = 'O' s2 = 'B' ) ( s1 = 'E' s2 = 'R' )
                    ( s1 = 'F' s2 = 'S' ) ( s1 = 'L' s2 = 'Y' )
                    ( s1 = 'P' s2 = 'C' ) ( s1 = 'Z' s2 = 'M' )
                  ).

  WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'A'        letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
  WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'BARK'     letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
  WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'BOOK'     letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
  WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'TREAT'    letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
  WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'COMMON'   letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
  WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'SQUAD'    letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
  WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'CONFUSE'  letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
Output:
True
True
False
True
False
True
True

Action![edit]

DEFINE COUNT="20"
CHAR ARRAY sideA="BXDCNGRTQFJHVAOEFLPZ"
CHAR ARRAY sideB="OKQPATEGDSWUINBRSYCM"
BYTE ARRAY used(COUNT)

BYTE FUNC ToUpper(BYTE c)
  IF c>='a AND c<='z THEN
    RETURN (c-'a+'A)
  FI
RETURN (c)

BYTE FUNC CanBeUsed(CHAR c)
  BYTE i

  FOR i=0 TO COUNT-1
  DO
    IF used(i)=0 AND (sideA(i+1)=c OR sideB(i+1)=c) THEN
      used(i)=1
      RETURN (1)
    FI
  OD
RETURN (0)

BYTE FUNC Check(CHAR ARRAY s)
  BYTE i
  CHAR c

  FOR i=0 TO COUNT-1
  DO used(i)=0 OD

  FOR i=1 TO s(0)
  DO
    c=ToUpper(s(i))
    IF CanBeUsed(c)=0 THEN
      RETURN (0)
    FI
  OD
RETURN (1)

PROC Test(CHAR ARRAY s)
  Print(s) Print(": ")
  IF Check(s) THEN
    PrintE("can be made")
  ELSE
    PrintE("can not be made")
  FI
RETURN

PROC Main()
  Test("a")
  Test("bARk")
  Test("book")
  Test("TReat")
  Test("coMMon")
  Test("SQuaD")
  Test("CoNfUsE")
RETURN
Output:

Screenshot from Atari 8-bit computer

a: can be made
bARk: can be made
book: can not be made
TReat: can be made
coMMon: can not be made
SQuaD: can be made
CoNfUsE: can be made

Acurity Architect[edit]

Using #HASH-OFF
FUNCTION bCAN_MAKE_WORD(zWord: STRING): BOOLEAN
  VAR sBlockCount: SHORT
  VAR sWordCount: SHORT
  VAR sWordLength: SHORT
  VAR zLetter: STRING
  VAR zBlock: STRING
  VAR zBlockList: STRING
  VAR zUsedBlocks: STRING
  VAR zWord: STRING
  //
  SET zWord = UPPER(zWord)
  SET zBlockList = "BO,XK,DQ,CP,NA,GT,RE,TG,QD,FS,JW,HU,VI,AN,OB,ER,FS,LY,PC,ZM"
  SET sWordLength = LENGTH(zWord)
  //
  DO sWordCount = 1 TO sWordLength
    DO sBlockCount = 1 TO OCCURS(zBlockList, ",")
      SET zLetter = SUBSTR(zWord, sWordCount, 1)
      SET zBlock = GET_TOKEN(zBlockList, ",", sBlockCount)
      IF INDEX(zBlock, zLetter, 1) > 0 AND INDEX(zUsedBlocks, zBlock + STR(sBlockCount), 1) = 0
        SET zUsedBlocks = zUsedBlocks + zBlock + STR(sBlockCount) + ","
        BREAK
      ENDIF
    ENDDO
  ENDDO
  RETURN OCCURS(zUsedBlocks, ",") = sWordLength 
ENDFUNCTION
Output:
bCAN_MAKE_WORD("A") returns TRUE
bCAN_MAKE_WORD("BARK") returns TRUE
bCAN_MAKE_WORD("BOOK") returns FALSE
bCAN_MAKE_WORD("TREAT") returns TRUE
bCAN_MAKE_WORD("COMMON") returns FALSE
bCAN_MAKE_WORD("SQUAD") returns TRUE
bCAN_MAKE_WORD("CONFUSE") returns TRUE

Ada[edit]

Build with gnatchop abc.ada; gnatmake abc_problem
with Ada.Characters.Handling;
use Ada.Characters.Handling;


package Abc is
    type Block_Faces is array(1..2) of Character;
    type Block_List is array(positive range <>) of Block_Faces;
    function Can_Make_Word(W: String; Blocks: Block_List) return Boolean;
end Abc;


package body Abc is

function Can_Make_Word(W: String; Blocks: Block_List) return Boolean is
    Used : array(Blocks'Range) of Boolean := (Others => False);
    subtype wIndex is Integer range W'First..W'Last;
    wPos : wIndex;
begin
    if W'Length = 0 then
        return True;
    end if;
    wPos := W'First;
    while True loop
        declare
            C : Character := To_Upper(W(wPos));
            X : constant wIndex := wPos;
        begin
            for I in Blocks'Range loop
                if (not Used(I)) then
                    if C = To_Upper(Blocks(I)(1)) or C = To_Upper(Blocks(I)(2)) then
                        Used(I) := True;
                        if wPos = W'Last then
                            return True;
                        end if;
                        wPos := wIndex'Succ(wPos);
                        exit;
                    end if;
                end if;
            end loop;
            if X = wPos then
                return False;
            end if;
        end;
    end loop;
    return False;
end Can_Make_Word;

end Abc;

with Ada.Text_IO, Ada.Strings.Unbounded, Abc;
use Ada.Text_IO, Ada.Strings.Unbounded, Abc;

procedure Abc_Problem is
    Blocks : Block_List := (
          ('B','O'), ('X','K'), ('D','Q'), ('C','P')
        , ('N','A'), ('G','T'), ('R','E'), ('T','G')
        , ('Q','D'), ('F','S'), ('J','W'), ('H','U')
        , ('V','I'), ('A','N'), ('O','B'), ('E','R')
        , ('F','S'), ('L','Y'), ('P','C'), ('Z','M')
    );
    function "+" (S : String) return Unbounded_String renames To_Unbounded_String;
    words : array(positive range <>) of Unbounded_String := (
          +"A"
        , +"BARK"
        , +"BOOK"
        , +"TREAT"
        , +"COMMON"
        , +"SQUAD"
        , +"CONFUSE"
        -- Border cases:
        -- , +"CONFUSE2"
        -- , +""
    );
begin
    for I in words'Range loop
        Put_Line ( To_String(words(I)) & ": " & Boolean'Image(Can_Make_Word(To_String(words(I)),Blocks)) );
    end loop;
end Abc_Problem;
Output:
A: TRUE
BARK: TRUE
BOOK: FALSE
TREAT: TRUE
COMMON: FALSE
SQUAD: TRUE
CONFUSE: TRUE

ALGOL 68[edit]

Works with: ALGOL 68G version Any - tested with release 2.8.win32
# determine whether we can spell words with a set of blocks                  #

# construct the list of blocks                                               #
[][]STRING blocks = ( ( "B", "O" ), ( "X", "K" ), ( "D", "Q" ), ( "C", "P" )
                    , ( "N", "A" ), ( "G", "T" ), ( "R", "E" ), ( "T", "G" )
                    , ( "Q", "D" ), ( "F", "S" ), ( "J", "W" ), ( "H", "U" )
                    , ( "V", "I" ), ( "A", "N" ), ( "O", "B" ), ( "E", "R" )
                    , ( "F", "S" ), ( "L", "Y" ), ( "P", "C" ), ( "Z", "M" )
                    );

# Returns TRUE if we can spell the word using the blocks, FALSE otherwise    #
# Returns TRUE for an empty string                                           #
PROC can spell = ( STRING word, [][]STRING blocks )BOOL:
    BEGIN

        # construct a set of flags to indicate whether the blocks are used   #
        # or not                                                             #
        [ 1 LWB blocks : 1 UPB blocks ]BOOL used;
        FOR block pos FROM LWB used TO UPB used
        DO
            used[ block pos ] := FALSE
        OD;

        # initialliy assume we can spell the word                            #
        BOOL result := TRUE;

        # check we can spell the word with the set of blocks                 #
        FOR word pos FROM LWB word TO UPB word WHILE result
        DO
            CHAR c = IF   is lower( word[ word pos ] )
                     THEN to upper( word[ word pos ] )
                     ELSE           word[ word pos ]
                     FI;

            # look through the unused blocks for the current letter          #
            BOOL found := FALSE;
            FOR block pos FROM 1 LWB blocks TO 1 UPB blocks
            WHILE NOT found
            DO
                IF  (  c = blocks[ block pos ][ 1 ][ 1 ]
                    OR c = blocks[ block pos ][ 2 ][ 1 ]
                    )
                AND NOT used[ block pos ]
                THEN
                    # found an unused block with the required letter         #
                    found             := TRUE;
                    used[ block pos ] := TRUE
                FI
            OD;

            result := found

        OD;

        result
    END; # can spell #


main: (

    # test the can spell procedure                                           #
    PROC test can spell = ( STRING word, [][]STRING blocks )VOID:
        write( ( ( "can spell: """
                 + word
                 + """ -> "
                 + IF can spell( word, blocks ) THEN "yes" ELSE "no" FI
                 )
               , newline
               )
             );

    test can spell( "A",       blocks );
    test can spell( "BaRK",    blocks );
    test can spell( "BOOK",    blocks );
    test can spell( "TREAT",   blocks );
    test can spell( "COMMON",  blocks );
    test can spell( "SQUAD",   blocks );
    test can spell( "CONFUSE", blocks )

)

Output:

can spell: "A" -> yes
can spell: "BaRK" -> yes
can spell: "BOOK" -> no
can spell: "TREAT" -> yes
can spell: "COMMON" -> no
can spell: "SQUAD" -> yes
can spell: "CONFUSE" -> yes

ALGOL W[edit]

% determine whether we can spell words with a set of blocks                  %
begin
    % Returns true  if we can spell the word using the blocks,               %
    %         false otherwise                                                %
    % As strings are fixed length in Algol W, the length of the string is    %
    % passed as a separate parameter                                         %
    logical procedure canSpell ( string(20) value word
                               ; integer    value wordLength
                               ) ;
    begin

        % convert a character to upper-case                                  %
        % assumes the letters are contiguous in the character set            %
        % as in ASCII and Unicode - not correct for EBCDIC                   %
        string(1) procedure toUpper( string(1) value c ) ;
            if c < "a" or c > "z" then c
                                  else code( ( decode( c ) - decode( "a" ) )
                                           + decode( "A" )
                                           ) ;

        logical       spellable;
        integer       wordPos,  blockPos;
        string(20)    letters1, letters2;

        % make local copies the faces so we can remove the used blocks       %
        letters1 := face1;
        letters2 := face2;

        % check we can spell the word with the set of blocks                 %
        spellable := true;
        wordPos   := 0;
        while wordPos < wordLength and spellable do begin
            string(1) letter;
            letter    := toUpper( word( wordPos // 1 ) );
            if letter not = " " then begin
                spellable := false;
                blockPos  := 0;
                while blockPos < 20 and not spellable do begin
                    if letter = letters1( blockPos // 1 )
                    or letter = letters2( blockPos // 1 )
                    then begin
                        % found the letter - remove the used block from the  %
                        % remaining blocks                                   %
                        letters1( blockPos // 1 ) := " ";
                        letters2( blockPos // 1 ) := " ";
                        spellable := true
                    end;
                    blockPos := blockPos + 1
                end
            end;
            wordPos := wordPos + 1;
        end;

        spellable
    end canSpell ;

    % the letters available on the faces of the blocks                       %
    string(20) face1, face2;
    face1 := "BXDCNGRTQFJHVAOEFLPZ";
    face2 := "OKQPATEGDSWUINBRSYCM";

    begin
        % test the can spell procedure                                       %
        procedure testCanSpell ( string(20) value word
                               ; integer    value wordLength
                               ) ;
            write( if canSpell( word, wordLength ) then "can   " else "cannot"
                 , " spell """
                 , word
                 , """"
                 );

        testCanSpell( "a",       1 );
        testCanSpell( "bark",    4 );
        testCanSpell( "BOOK",    4 );
        testCanSpell( "treat",   5 );
        testCanSpell( "commoN",  6 );
        testCanSpell( "Squad",   5 );
        testCanSpell( "confuse", 7 )
    end
end.
Output:
can    spell "a                   "
can    spell "bark                "
cannot spell "BOOK                "
can    spell "treat               "
cannot spell "commoN              "
can    spell "Squad               "
can    spell "confuse             "

Apex[edit]

static Boolean canMakeWord(List<String> src_blocks, String word) {
    if (String.isEmpty(word)) {
        return true;
    }

    List<String> blocks = new List<String>();
    for (String block : src_blocks) {
        blocks.add(block.toUpperCase());
    }
    
    for (Integer i = 0; i < word.length(); i++) {
        Integer blockIndex = -1;
        String c = word.mid(i, 1).toUpperCase();
        
        for (Integer j = 0; j < blocks.size(); j++) {
            if (blocks.get(j).contains(c)) {
                blockIndex = j;
                break;
            }
        }
        
        if (blockIndex == -1) {
            return false;
        } else {
            blocks.remove(blockIndex);
        }
    }
        
    return true;
}

List<String> blocks = new List<String>{
    'BO', 'XK', 'DQ', 'CP', 'NA',
    'GT', 'RE', 'TG', 'QD', 'FS', 
    'JW', 'HU', 'VI', 'AN', 'OB', 
    'ER', 'FS', 'LY', 'PC', 'ZM'
};
System.debug('"": ' + canMakeWord(blocks, ''));
System.debug('"A": ' + canMakeWord(blocks, 'A'));
System.debug('"BARK": ' + canMakeWord(blocks, 'BARK'));
System.debug('"book": ' + canMakeWord(blocks, 'book'));
System.debug('"treat": ' + canMakeWord(blocks, 'treat'));
System.debug('"COMMON": ' + canMakeWord(blocks, 'COMMON'));
System.debug('"SQuAd": ' + canMakeWord(blocks, 'SQuAd'));
System.debug('"CONFUSE": ' + canMakeWord(blocks, 'CONFUSE'));
Output:
"": true
"A": true
"BARK": true
"book": false
"treat": true
"COMMON": false
"SQuAd": true
"CONFUSE": true

APL[edit]

Works with: Dyalog APL version 16.0
abc{{0=⍴⍵:1  0=⍴h⍵:0  (t1)~¨h:1  (1h),t}¨∘.}
Output:
      )COPY dfns ucase
      b W←(≠∘' '⊆⊢)∘ucase¨'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM' 'A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE'
      b∘abc¨W
1 1 0 1 0 1 1

AppleScript[edit]

Imperative[edit]

set blocks to {"bo", "xk", "dq", "cp", "na", "gt", "re", "tg", "qd", "fs", ¬
    "jw", "hu", "vi", "an", "ob", "er", "fs", "ly", "pc", "zm"}

canMakeWordWithBlocks("a", blocks)
canMakeWordWithBlocks("bark", blocks)
canMakeWordWithBlocks("book", blocks)
canMakeWordWithBlocks("treat", blocks)
canMakeWordWithBlocks("common", blocks)
canMakeWordWithBlocks("squad", blocks)
canMakeWordWithBlocks("confuse", blocks)

on canMakeWordWithBlocks(theString, constBlocks)
    copy constBlocks to theBlocks
    if theString = "" then return true
    set i to 1
    repeat
        if i > (count theBlocks) then exit repeat
        if character 1 of theString is in item i of theBlocks then
            set item i of theBlocks to missing value
            set theBlocks to strings of theBlocks
            if canMakeWordWithBlocks(rest of characters of theString as string, theBlocks) then
                return true
            end if
        end if
        set i to i + 1
    end repeat
    return false
end canMakeWordWithBlocks

Functional[edit]

use AppleScript version "2.4"
use framework "Foundation"

----------------------- ABC Problem -----------------------

-- spellWith :: [String] -> [Char] -> [[String]]
on spellWith(blocks, cs)
    if 0 < length of cs then
        set x to item 1 of cs
        script go
            on |λ|(b)
                if b contains x then
                    map(my cons(b), ¬
                        spellWith(|delete|(b, blocks), rest of cs))
                else
                    {}
                end if
            end |λ|
        end script
        concatMap(go, blocks)
    else
        {{}}
    end if
end spellWith


-------------------------- TEST ---------------------------
on run
    set blocks to ¬
        words of "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
    
    script test
        on |λ|(w)
            justifyRight(9, space, quoted("'", w)) & " -> " & ¬
                ({}  spellWith(blocks, characters of toUpper(w)))
        end |λ|
    end script
    
    unlines(map(test, ¬
        ["", "A", "BARK", "BoOK", "TrEAT", "COmMoN", "SQUAD", "conFUsE"]))
end run


-------------------- GENERIC FUNCTIONS --------------------

-- Just :: a -> Maybe a
on Just(x)
    -- Constructor for an inhabited Maybe (option type) value.
    -- Wrapper containing the result of a computation.
    {type:"Maybe", Nothing:false, Just:x}
end Just


-- Nothing :: Maybe a
on Nothing()
    -- Constructor for an empty Maybe (option type) value.
    -- Empty wrapper returned where a computation is not possible.
    {type:"Maybe", Nothing:true}
end Nothing


-- elemIndex :: Eq a => a -> [a] -> Maybe Int
on elemIndex(x, xs)
    set lng to length of xs
    repeat with i from 1 to lng
        if x = (item i of xs) then return Just(i)
    end repeat
    return Nothing()
end elemIndex


-- concatMap :: (a -> [b]) -> [a] -> [b]
on concatMap(f, xs)
    set lng to length of xs
    set acc to {}
    tell mReturn(f)
        repeat with i from 1 to lng
            set acc to acc & (|λ|(item i of xs, i, xs))
        end repeat
    end tell
    return acc
end concatMap


-- cons :: a -> [a] -> [a]
on cons(x)
    script
        on |λ|(xs)
            {x} & xs
        end |λ|
    end script
end cons


-- delete :: Eq a => a -> [a] -> [a]
on |delete|(x, xs)
    set mbIndex to elemIndex(x, xs)
    set lng to length of xs
    
    if Nothing of mbIndex then
        xs
    else
        if 1 < lng then
            set i to Just of mbIndex
            if 1 = i then
                items 2 thru -1 of xs
            else if lng = i then
                items 1 thru -2 of xs
            else
                tell xs to items 1 thru (i - 1) & items (i + 1) thru -1
            end if
        else
            {}
        end if
    end if
end |delete|


-- justifyRight :: Int -> Char -> String -> String
on justifyRight(n, cFiller, strText)
    if n > length of strText then
        text -n thru -1 of ((replicate(n, cFiller) as text) & strText)
    else
        strText
    end if
end justifyRight


-- mReturn :: First-class m => (a -> b) -> m (a -> b)
on mReturn(f)
    -- 2nd class handler function lifted into 1st class script wrapper. 
    if script is class of f then
        f
    else
        script
            property |λ| : f
        end script
    end if
end mReturn


-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
    -- The list obtained by applying f
    -- to each element of xs.
    tell mReturn(f)
        set lng to length of xs
        set lst to {}
        repeat with i from 1 to lng
            set end of lst to |λ|(item i of xs, i, xs)
        end repeat
        return lst
    end tell
end map


-- quoted :: Char -> String -> String
on quoted(c, s)
    -- string flanked on both sides
    -- by a specified quote character.
    c & s & c
end quoted


-- replicate :: Int -> String -> String
on replicate(n, s)
    set out to ""
    if n < 1 then return out
    set dbl to s
    
    repeat while (n > 1)
        if (n mod 2) > 0 then set out to out & dbl
        set n to (n div 2)
        set dbl to (dbl & dbl)
    end repeat
    return out & dbl
end replicate


-- toUpper :: String -> String
on toUpper(str)
    set ca to current application
    ((ca's NSString's stringWithString:(str))'s ¬
        uppercaseStringWithLocale:(ca's NSLocale's currentLocale())) as text
end toUpper


-- unlines :: [String] -> String
on unlines(xs)
    -- A single string formed by the intercalation
    -- of a list of strings with the newline character.
    set {dlm, my text item delimiters} to ¬
        {my text item delimiters, linefeed}
    set s to xs as text
    set my text item delimiters to dlm
    s
end unlines
Output:
       '' -> true
      'A' -> true
   'BARK' -> true
   'BoOK' -> false
  'TrEAT' -> true
 'COmMoN' -> false
  'SQUAD' -> true
'conFUsE' -> true

ARM Assembly[edit]

Works with: as version Raspberry Pi
/* ARM assembly Raspberry PI  */
/*  program problemABC.s   */ 

/* REMARK 1 : this program use routines in a include file 
   see task Include a file language arm assembly 
   for the routine affichageMess conversion10 
   see at end of this program the instruction include */
/* for constantes see task include a file in arm assembly */
/************************************/
/* Constantes                       */
/************************************/
.include "../constantes.inc"
.equ TRUE, 1
.equ FALSE, 0

/*********************************/
/* Initialized data              */
/*********************************/
.data
szMessTitre1:        .asciz "Can_make_word: @ \n"
szMessTrue:          .asciz "True.\n"
szMessFalse:         .asciz "False.\n"
szCarriageReturn:    .asciz "\n"

szTablBloc:          .asciz "BO"
                     .asciz "XK"
                     .asciz "DQ"
                     .asciz "CP"
                     .asciz "NA"
                     .asciz "GT"
                     .asciz "RE"
                     .asciz "TG"
                     .asciz "QD"
                     .asciz "FS"
                     .asciz "JW"
                     .asciz "HU"
                     .asciz "VI"
                     .asciz "AN"
                     .asciz "OB"
                     .asciz "ER"
                     .asciz "FS"
                     .asciz "LY"
                     .asciz "PC"
                     .asciz "ZM"
                     .equ NBBLOC, (. -  szTablBloc) / 3
                     
szWord1:             .asciz "A"
szWord2:             .asciz "BARK"
szWord3:             .asciz "BOOK"
szWord4:             .asciz "TREAT"
szWord5:             .asciz "COMMON"
szWord6:             .asciz "SQUAD"
szWord7:             .asciz "CONFUSE"
/*********************************/
/* UnInitialized data            */
/*********************************/
.bss
.align 4
itabTopBloc:         .skip 4 * NBBLOC
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main 
main:                                @ entry of program 
    ldr r0,iAdrszWord1
    bl traitBlock                    @ control word

    ldr r0,iAdrszWord2
    bl traitBlock                    @ control word
    
    ldr r0,iAdrszWord3
    bl traitBlock                    @ control word
    
    ldr r0,iAdrszWord4
    bl traitBlock                    @ control word
        
    ldr r0,iAdrszWord5
    bl traitBlock                    @ control word
        
    ldr r0,iAdrszWord6
    bl traitBlock                    @ control word
        
    ldr r0,iAdrszWord7
    bl traitBlock                    @ control word

100:                                  @ standard end of the program 
    mov r0, #0                        @ return code
    mov r7, #EXIT                     @ request to exit program
    svc #0                            @ perform the system call
 
iAdrszCarriageReturn:     .int szCarriageReturn
iAdrszWord1:              .int szWord1
iAdrszWord2:              .int szWord2
iAdrszWord3:              .int szWord3
iAdrszWord4:              .int szWord4
iAdrszWord5:              .int szWord5
iAdrszWord6:              .int szWord6
iAdrszWord7:              .int szWord7
/******************************************************************/
/*          traitement                                           */ 
/******************************************************************/
/* r0 contains word */
traitBlock:
    push {r1,lr}        @ save registers
    mov r1,r0
    ldr r0,iAdrszMessTitre1   @ insertion word in message
    bl strInsertAtCharInc
    bl affichageMess          @ display title message
    mov r0,r1
    bl controlBlock           @ control 
    cmp r0,#TRUE              @ ok ?
    bne 1f
    ldr r0,iAdrszMessTrue     @ yes
    bl affichageMess
    b 100f
1:                            @ no
    ldr r0,iAdrszMessFalse
    bl affichageMess
100:
    pop {r1,lr}
    bx lr                     @ return 
iAdrszMessTitre1:         .int szMessTitre1
iAdrszMessFalse:          .int szMessFalse
iAdrszMessTrue:           .int szMessTrue
/******************************************************************/
/*        control if letters are in block                       */ 
/******************************************************************/
/* r0 contains word */
controlBlock:
    push {r1-r9,lr}        @ save registers
    mov r5,r0              @ save word address
    ldr r4,iAdritabTopBloc
    ldr r6,iAdrszTablBloc
    mov r2,#0
    mov r3,#0
1:                          @ init table top block used
    str r3,[r4,r2,lsl #2]
    add r2,r2,#1
    cmp r2,#NBBLOC
    blt 1b
    mov r2,#0
2:                          @ loop to load letters 
    ldrb r3,[r5,r2]
    cmp r3,#0
    beq 10f                 @ end
    and r3,r3,#0xDF         @ transform in capital letter
    mov r8,#0
3:                          @ begin loop control block
    ldr r7,[r4,r8,lsl #2]   @ block already used ?
    cmp r7,#0
    bne 5f                  @ yes
    add r9,r8,r8,lsl #1     @ no -> index * 3
    ldrb r7,[r6,r9]         @ first block letter
    cmp r3,r7               @ equal ?
    beq 4f
    add r9,r9,#1
    ldrb r7,[r6,r9]         @ second block letter
    cmp r3,r7               @ equal ?
    beq 4f
    b 5f
4:
    mov r7,#1               @ top block
    str r7,[r4,r8,lsl #2]   @ block used
    add r2,r2,#1
    b 2b                    @ next letter
5:
    add r8,r8,#1
    cmp r8,#NBBLOC
    blt 3b
    mov r0,#FALSE           @ no letter find on block -> false
    b 100f 
10:                         @ all letters are ok
    mov r0,#TRUE
100:
    pop {r1-r9,lr}
    bx lr                   @ return 
iAdritabTopBloc:   .int itabTopBloc
iAdrszTablBloc:    .int szTablBloc
/***************************************************/
/*      ROUTINES INCLUDE                           */
/***************************************************/
.include "../affichage.inc"
Can_make_word: A
True.
Can_make_word: BARK
True.
Can_make_word: BOOK
False.
Can_make_word: TREAT
True.
Can_make_word: COMMON
False.
Can_make_word: SQUAD
True.
Can_make_word: CONFUSE
True.

Arturo[edit]

blocks: map [
    [B O] [X K] [D Q] [C P] [N A] [G T] [R E] 
    [T G] [Q D] [F S] [J W] [H U] [V I] [A N] 
    [O B] [E R] [F S] [L Y] [P C] [Z M]
] => [ join map & => [to :string &]]

charInBlock: function [ch,bl][
    loop.with:'i bl 'b ->
        if contains? b upper ch [
            return i
        ]
    return ø
]

canMakeWord?: function [wrd][
    ref: new blocks
    loop split wrd 'chr [
        cib: charInBlock chr ref
        if? cib = ø [ return false ]
        else        [ ref: remove ref .index cib ]
    ]
    return true
]

loop ["A" "BaRk" "bOoK" "tReAt" "CoMmOn" "SqUaD" "cONfUsE"] 'wrd
    -> print [wrd "=>" canMakeWord? wrd]
Output:
A => true 
BaRk => true 
bOoK => false 
tReAt => true 
CoMmOn => false 
SqUaD => true 
cONfUsE => true

Astro[edit]

fun abc(s, ls):
    if ls.isempty:
        return true
    for i in indices(list) where s[end] in list[i]:
        return abc(s[:end-1], remove!(copy(list), at: i))
    false

let test = ["A", "BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE"]
let ls = ["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS", "JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"]

for s in test:
    print "($|>8|{s} ${abc(s, list)})"

AutoHotkey[edit]

Function

isWordPossible(blocks, word){
	o := {}
	loop, parse, blocks, `n, `r
		o.Insert(A_LoopField)
	loop, parse, word
		if !(r := isWordPossible_contains(o, A_LoopField, word))
			return 0
	return 1
}
isWordPossible_contains(byref o, letter, word){
	loop 2 {
		for k,v in o
			if Instr(v,letter)
			{
				StringReplace, op, v,% letter
				if RegExMatch(op, "[" word "]")
					sap := k
				else added := 1 , sap := k
				if added
					return "1" o.remove(sap)
			}
		added := 1
	}
}

Test Input (as per question)

blocks := "
(
BO
XK
DQ
CP
NA
GT
RE
TG
QD
FS
JW
HU
VI
AN
OB
ER
FS
LY
PC
ZM
)"

wordlist := "
(
A
BARK
BOOK
TREAT
COMMON
SQUAD
CONFUSE
)"

loop, parse, wordlist, `n
	out .= A_LoopField " - " isWordPossible(blocks, A_LoopField) "`n"
msgbox % out
Output:
A - 1
BARK - 1
BOOK - 0
TREAT - 1
COMMON - 0
SQUAD - 1
CONFUSE - 1

AWK[edit]

Here are 2 slightly different versions:

#!/usr/bin/awk -f
# tested with mawk 1.3.3 on Raspberry Pi 3
#        also GNU awk 3.1.5, busybox 1.21.1 and 1.27.1 on AMD Sempron 2800+
#
function setblocks() {
# key to the algorithm is the representation of a block
# each block is represented by 4 characters in the string "blocks"
# for example, the "BO" block becomes "-BO-"
#
blocks="-BO--XK--DQ--CP--NA--GT--RE--TG--QD--FS--JW--HU--VI--AN--OB--ER--FS--LY--PC--ZM-"
true=1
false=0
}
function found(letter){
#
# the function "found" scans for the letter on the top of a block
# using the pattern "-B", for example, to find a "B",
# returning "true" (or 1) if found
# if not found on the top, look on the bottoms using the pattern "B-"
# again returning "true" if found
# if the letter is found on either top or bottom, the 4 character block is set to "----"
# so that block is unavailable 
# finally, if no available copy of letter is found,
# the function returns "false" (0)
position= index(blocks,"-" letter)
if (position > 0)
   { 
  blocks = substr(blocks,1,position-1) "----" substr(blocks,position+4)
  return true
   }
position = index(blocks,letter "-")
if (position > 0)
   {blocks = substr(blocks,1,position-3) "----" substr(blocks,position+2)
     return true
    }
return false
}
# awk's BEGIN statement allows for initialization before processing input;
# in this case, initializing the string "blocks"
#
BEGIN{
setblocks()
}
# in awk, the input record is contained in the string variable "$0"
# the main process checks each letter in turn to see if it is on a usable block,
# summing the values returned by "found"
# if the sum equals the number of input characters the word can be spelled with the blocks
# otherwise it is not possible
#
{
nchars=length($0)
possible=false
for (i=1;i<=nchars;i++){
     possible=possible + found(substr($0,i,1))
}
if (possible==nchars) print $0 " is possible"
   else print $0 " is not possible"
setblocks()
}

and -----------------
#!/usr/bin/awk -f
# tested with mawk 1.3.3 on Raspberry Pi 3
#        also GNU awk 3.1.5, busybox 1.21.1 and 1.27.1 on AMD Sempron 2800+
#
function setblocks() {
#
#  key to the algorithm is the representation of the blocks
# each block is represented by 1 character in the string "tops"
# and by 1 character in the string "bottoms"
#
   tops="BXDCNGRTQFJHVAOEFLPZ"
bottoms="OKQPATEGDSWUINBRSYCM"
true=1
false=0
}
function found(letter){
#
# the function "found" scans first the string "tops" for a letter and
# then the string "bottoms" if the letter is not in "tops"
# if the letter is found, it marks "tops" and "bottoms" to show
# the block is unavailable by changing the letters on the block to "-"
# and returns "true" (1); if the letter is not found
# the function returns "false" (0)
#
position= index(tops,letter)
if (position > 0)
   { 
  tops = substr(tops,1,position-1) "-" substr(tops,position+1)
  bottoms = substr(bottoms,1,position-1) "-" substr(bottoms,position+1)
  return true
   }
position = index(bottoms,letter)
if (position > 0)
   {bottoms = substr(bottoms,1,position-1) "-" substr(bottoms,position+1)
    tops = substr(tops,1,position-1) "-" substr(tops,position+1)
     return true
    }
return false
}
# awk's BEGIN statement allows for initialization before processing input;
# in this case, initializing the string "blocks"
#
BEGIN{
setblocks()
}
# in awk, the input record is contained in the string variable "$0"
# the main process checks each letter in turn to see if it is on a usable block,
# summing the values returned by "found"
# if the sum equals the number of input characters the word can be spelled with the blocks
# otherwise it is not possible
#
{
nchars=length($0)
possible=false
for (i=1;i<=nchars;i++){
     possible=possible + found(substr($0,i,1))
}
if (possible==nchars) print $0 " is possible"
   else print $0 " is not possible"
setblocks()
}
Output:
pi@raspberrypi:~/Documents/rosettacode $ ./abcProblem.awk 
A
A is possible
BARK
BARK is possible
BOOK
BOOK is not possible
TREAT
TREAT is possible
COMMON
COMMON is not possible
SQUAD
SQUAD is possible
CONFUSE
CONFUSE is possible
^C
pi@raspberrypi:~/Documents/rosettacode $ 

BaCon[edit]

CONST info$ = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"

DATA "A", "BARK", "BOOK", "TREAT", "Common", "Squad", "Confuse"

WHILE TRUE
    READ word$

    IF NOT(LEN(word$)) THEN BREAK

    block$ = info$

    count = AMOUNT(block$)

    FOR y = 1 TO LEN(word$)
        FOR x = 1 TO AMOUNT(block$)
            IF TALLY(TOKEN$(block$, x), MID$(UCASE$(word$), y, 1)) THEN
                block$ = DEL$(block$, x)
                BREAK
            END IF
        NEXT
    NEXT

    PRINT word$, IIF$(LEN(word$) = count-AMOUNT(block$), "True", "False") FORMAT "%-10s: %s\n"
WEND
Output:
A         : True
BARK      : True
BOOK      : False
TREAT     : True
Common    : False
Squad     : True
Confuse   : True

BASIC[edit]

Works with:VB-DOS, QB64, QBasic, QuickBASIC

' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' '
' ABC_Problem                                       '
'                                                   '
' Developed by A. David Garza Marín in VB-DOS for   '
' RosettaCode. November 29, 2016.                   '
' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' '

' Comment the following line to run it in QB or QBasic
OPTION EXPLICIT  ' Modify to OPTION _EXPLICIT for QB64

' SUBs and FUNCTIONs
DECLARE SUB doCleanBlocks ()
DECLARE FUNCTION ICanMakeTheWord (WhichWord AS STRING) AS INTEGER
DECLARE SUB doReadBlocks ()

' rBlock Data Type
TYPE regBlock
  Block AS STRING * 2
  Used AS INTEGER
END TYPE

' Initialize
CONST False = 0, True = NOT False, HMBlocks = 20
DATA "BO", "XK", "DQ", "CP", "NA", "GT","RE", "TG"
DATA "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER"
DATA "FS", "LY", "PC","ZM"

DIM rBlock(1 TO HMBlocks) AS regBlock
DIM i AS INTEGER, aWord AS STRING, YorN AS STRING

doReadBlocks ' Read the data in the blocks

'-------------- Main program cycle ------------------
CLS
PRINT "This program has the following blocks: ";
FOR i = 1 TO HMBlocks
  PRINT rBlock(i).Block; "|";
NEXT i
PRINT : PRINT
PRINT "Please, write a word or a short sentence to see if the available"
PRINT "blocks can make it. If so, I will tell you."
DO
  doCleanBlocks ' Clean all blocks
  PRINT
  INPUT "Which is the word"; aWord
  aWord = LTRIM$(RTRIM$(aWord))

  IF aWord <> "" THEN
    IF ICanMakeTheWord(aWord) THEN
      PRINT "Yes, i can make it."
    ELSE
      PRINT "No, I can't make it."
    END IF
  ELSE
    PRINT "At least, you need to type a letter."
  END IF

  PRINT
  PRINT "Do you want to try again (Y/N) ";
  DO
    YorN = INPUT$(1)
    YorN = UCASE$(YorN)
  LOOP UNTIL YorN = "Y" OR YorN = "N"
  PRINT YorN

LOOP UNTIL YorN = "N"
' -------------- End of Main program ----------------
END

SUB doCleanBlocks ()
  ' Var
  SHARED rBlock() AS regBlock
  DIM i AS INTEGER

  ' Will clean the Used status of all blocks
  FOR i = 1 TO HMBlocks
    rBlock(i).Used = False
  NEXT i

END SUB

SUB doReadBlocks ()
  ' Var
  SHARED rBlock() AS regBlock
  DIM i AS INTEGER

  ' Will read the block values from DATA
  FOR i = 1 TO HMBlocks
    READ rBlock(i).Block
  NEXT i
END SUB

FUNCTION ICanMakeTheWord (WhichWord AS STRING) AS INTEGER ' Comment AS INTEGER to run in QBasic, QB64 and QuickBASIC
  ' Var
  SHARED rBlock() AS regBlock
  DIM i AS INTEGER, l AS INTEGER, j AS INTEGER, iYesICan AS INTEGER
  DIM c AS STRING, sUWord AS STRING

  ' Will evaluate if can make the word
  sUWord = UCASE$(WhichWord)
  l = LEN(sUWord)
  i = 0

  DO
    i = i + 1
    iYesICan = False
    c = MID$(sUWord, i, 1)
    j = 0
    DO
      j = j + 1
      IF NOT rBlock(j).Used THEN
        iYesICan = (INSTR(rBlock(j).Block, c) > 0)
        rBlock(j).Used = iYesICan
      END IF
    LOOP UNTIL j >= HMBlocks OR iYesICan

  LOOP UNTIL i >= l OR NOT iYesICan

  ' The result will depend on the last value of
  '  iYesICan variable. If the last value is True
  '  is because the function found even the last
  '  letter analyzed.
  ICanMakeTheWord = iYesICan

END FUNCTION

Commodore BASIC[edit]

Translation of: Sinclair ZX-81 BASIC
10 W$ = "A" : GOSUB 100
20 W$ = "BARK" : GOSUB 100
30 W$ = "BOOK" : GOSUB 100
40 W$ = "TREAT" : GOSUB 100
50 W$ = "COMMON" : GOSUB 100
60 W$ = "SQUAD" : GOSUB 100
70 W$ = "CONFUSE" : GOSUB 100
80 END
90 REM ********************************
100 B$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
110 FOR I=1 TO LEN(W$)
120 :  BL = LEN(B$)
130 :  FOR J=1 TO BL STEP 2
140 :    C$=MID$(B$,J,1): D$=MID$(B$,J+1,1)
150 :    X$=MID$(W$,I,1)
160 :    IF C$<>X$ AND D$<>X$ THEN GOTO 190
170 :    B$ = LEFT$(B$,J-1)+RIGHT$(B$,BL-J-1)
180 :    GOTO 210
190 : NEXT J
200 : IF J>BL-1 THEN GOTO 240
210 NEXT I
220 PRINT W$" -> YES"
230 RETURN
240 PRINT W$" -> NO"
250 RETURN
Output:
A -> YES
BARK -> YES
BOOK -> NO
TREAT -> YES
COMMON -> NO
SQUAD -> YES
CONFUSE -> YES

The above greedy algorithm works on the sample data, but fails on other data - for example, it will declare that you cannot spell the word ABBA using the blocks (AB),(AB),(AC),(AC), because it will use the two AB blocks for the first two letters "AB", leaving none for the second "B". This recursive solution is more thorough about confirming negatives and handles that case correctly:

100 REM RECURSIVE SOLUTION
110 MS=100:REM MAX STACK DEPTH
120 DIM BL$(MS):REM BLOCKS LEFT
130 DIM W$(MS):REM REMAINING LETTERS
140 DIM I(MS):REM LOOP CONTROL VARIABLE
150 DIM RV(MS):REM RETURN VALUE
160 SP=-1:REM STACK POINTER
170 READ BL$
180 PRINT "USING BLOCKS: "
190 FOR I=1 TO LEN(BL$) STEP 2
200 : PRINT"("MID$(BL$,I,2)")";
210 NEXT I
220 PRINT CHR$(13)
230 READ W$
240 IF W$="" THEN 320
250 PRINT W$;"->";
260 SP=SP+1:BL$(SP)=BL$:W$(SP)=W$
270 GOSUB 350
280 IF RV(SP) THEN PRINT "YES": GOTO 300
290 PRINT "NO"
300 SP=SP-1
310 GOTO 230
320 READ BL$
330 IF BL$ THEN PRINT:GOTO 180
340 END
350 IF LEN(W$(SP))=0 THEN RV(SP)=-1:RETURN
360 I(SP)=1
370 IF I(SP)>=LEN(BL$(SP)) THEN RV(SP)=0:RETURN
380 IF MID$(BL$(SP),I(SP),1) = LEFT$(W$(SP),1) THEN 410
390 IF MID$(BL$(SP),I(SP)+1,1) = LEFT$(W$(SP),1) THEN 410
400 GOTO 450
410 W$(SP+1)=MID$(W$(SP),2)
420 BL$(SP+1)=LEFT$(BL$(SP),I(SP)-1)+MID$(BL$(SP),I(SP)+2)
430 SP=SP+1:GOSUB 350:SP=SP-1
440 IF RV(SP+1) THEN RV(SP)=-1:RETURN
450 I(SP)=I(SP)+2:GOTO 370
460 DATA BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM
470 DATA A, BORK, BOOK, TREAT, COMMON, SQUAD, CONFUSE, ""
480 DATA ABABACAC,ABBA,""
490 DATA ""
Output:
USING BLOCKS:
(BO)(XK)(DQ)(CP)(NA)(GT)(RE)(TG)(QD)(FS)
(JW)(HU)(VI)(AN)(OB)(ER)(FS)(LY)(PC)(ZM)

A->YES
BORK->YES
BOOK->NO
TREAT->YES
COMMON->NO
SQUAD->YES
CONFUSE->YES

USING BLOCKS:
(AB)(AB)(AC)(AC)

ABBA->YES

Sinclair ZX81 BASIC[edit]

Works with 1k of RAM. A nice unstructured algorithm. Unfortunately the requirement that it be case-insensitive is moot, because the ZX81 does not support lower-case letters.

 10 LET B$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
 20 INPUT W$
 30 FOR I=1 TO LEN W$
 40 FOR J=1 TO LEN B$ STEP 2
 50 IF B$(J)<>W$(I) AND B$(J+1)<>W$(I) THEN GOTO 100
 60 LET B$=B$( TO J-1)+B$(J+2 TO )
 70 NEXT I
 80 PRINT "YES"
 90 STOP
100 NEXT J
110 PRINT "NO"
Input:
A
Output:
YES
Input:
BARK
Output:
YES
Input:
BOOK
Output:
NO
Input:
TREAT
Output:
YES
Input:
COMMON
Output:
NO
Input:
SQUAD
Output:
YES
Input:
CONFUSE
Output:
YES

Batch File[edit]

@echo off
::abc.bat
::
::Batch file to evaluate if a given string can be represented with a set of
::20 2-faced blocks.
::

::Check if a string was provided
if "%1"=="" goto ERROR

::Define blocks. Separate blocks by ':', and terminat with '::'
set "FACES=BO:XK:DQ:CP:NA:GT:RE:TG:QD:FS:JW:HU:VI:AN:OB:ER:FS:LY:PC:ZM::"
set INPUT=%1
set "COUNTER=0"

::The main loop steps through the input string, checking if an available
::block exists for each character
:LOOP_MAIN

  ::Get character, increase counter, and test if there are still characters
  call set "char=%%INPUT:~%COUNTER%,1%%"
  set /a "COUNTER+=1"
  if "%CHAR%"=="" goto LOOP_MAIN_END

  set "OFFSET=0"
  :LOOP_2

    ::Read in two characters (one block)
    call set "BLOCK=%%FACES%:~%OFFSET%,2%%"

    ::Test if the all blocks were checked. If so, no match was found
    if "%BLOCK%"==":" goto FAIL

    ::Test if current input string character is in the current block
    if /i "%BLOCK:~0,1%"=="%CHAR%" goto FOUND
    if /i "%BLOCK:~1,1%"=="%CHAR%" goto FOUND

    ::Increase offset to point to the next block
    set /a "OFFSET+=3"

  goto LOOP_2
  :LOOP_2_END

  ::If found, blank out the block used
  :FOUND
  call set "FACES=%%FACES:%BLOCK%:=  :%%"

goto LOOP_MAIN
:LOOP_MAIN_END

echo %0: It is possible to write the '%INPUT%' with my blocks.
goto END

:FAIL
echo %0: It is NOT possible to write the '%INPUT%' with my blocks.
goto END

:ERROR
echo %0: Please enter a string to evaluate
echo.

:END

BBC BASIC[edit]

      BLOCKS$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
      PROCcan_make_word("A")
      PROCcan_make_word("BARK")
      PROCcan_make_word("BOOK")
      PROCcan_make_word("TREAT")
      PROCcan_make_word("COMMON")
      PROCcan_make_word("SQUAD")
      PROCcan_make_word("Confuse")
      END

      DEF PROCcan_make_word(word$)
      LOCAL b$,p%
      b$=BLOCKS$
      PRINT word$ " -> ";
      p%=INSTR(b$,CHR$(ASCword$ AND &DF))
      WHILE p%>0 AND word$>""
        MID$(b$,p%-1+(p% MOD 2),2)=".."
        word$=MID$(word$,2)
        p%=INSTR(b$,CHR$(ASCword$ AND &DF))
      ENDWHILE
      IF word$>"" PRINT "False" ELSE PRINT "True"
      ENDPROC
Output:
A -> True
BARK -> True
BOOK -> False
TREAT -> True
COMMON -> False
SQUAD -> True
Confuse -> True

BCPL[edit]

get "libhdr"

let canMakeWord(word) = valof
$(  let blocks = "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
    let avl = vec 40/BYTESPERWORD
    for i=0 to 39 do avl%i := blocks%(i+1)
    for i=1 to word%0
    $(  for j=0 to 39
        $(  let ch = word%i
            // make letter uppercase
            if 'a' <= ch <= 'z' then ch := ch - 32
            if ch = avl%j then
            $(  // this block is no longer available
                avl%j := 0
                avl%(j neqv 1) := 0
                // but we did find a block
                goto next
            $)
        $)
        resultis false // no block found
        next: loop
    $)
    resultis true 
$)

let show(word) be
    writef("%S: %S*N", word, canMakeWord(word) -> "yes", "no")

let start() be
$(  show("A")
    show("BARK")
    show("book")
    show("Treat")
    show("CoMmOn")
    show("SQUAD")
    show("CONFUSE")
$)
Output:
A: yes
BARK: yes
book: no
Treat: yes
CoMmOn: no
SQUAD: yes
CONFUSE: yes

BQN[edit]

ABC ← {
   Matches ← ⊑⊸(⊑∘∊¨)˜ /⊣            # blocks matching current letter
   Others  ← <˘∘⍉∘(»⊸≥∨`)∘(≡⌜)/¨<∘⊣ # blocks without current matches
   𝕨(×∘≠∘⊢ ◶ ⟨1˙,                   # if the word is empty, it can be made
       Matches(×∘≠∘⊣ ◶ ⟨0˙,         # if no matching blocks, it cannot
           ∨´(𝕨 Others⊣) 𝕊¨ 1<∘↓⊢   # otherwise, remove block and try remaining letters
       ⟩)⊢
   ⟩) (⊢-32×1="a{"⍋⊢)𝕩
}

blocks←⟨"BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
        "JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"⟩

words←⟨"A","bark","BOOK","TrEaT","Common","Squad","Confuse"⟩

> {(<𝕩) ∾ blocks ABC 𝕩}¨ words
Output:
┌─             
╵ "A"       1  
  "bark"    1  
  "BOOK"    0  
  "TrEaT"   1  
  "Common"  0  
  "Squad"   1  
  "Confuse" 1  
              ┘

Bracmat[edit]

(
  ( can-make-word
  =   ABC blocks
    .       (B O)
          + (X K)
          + (D Q)
          + (C P)
          + (N A)
          + (G T)
          + (R E)
          + (T G)
          + (Q D)
          + (F S)
          + (J W)
          + (H U)
          + (V I)
          + (A N)
          + (O B)
          + (E R)
          + (F S)
          + (L Y)
          + (P C)
          + (Z M)
        : ?blocks
      & ( ABC
        =   letter blocks A Z
          .   !arg:(.?)
            |   !arg:(@(?:%?letter ?arg).?blocks)
              &   !blocks
                :   ?
                  + ?*(? !letter ?:?block)
                  + (?&ABC$(!arg.!blocks+-1*!block))
        )
      &   out
        $ ( !arg
            ( ABC$(upp$!arg.!blocks)&yes
            | no
            )
          )
  )
& can-make-word'A
& can-make-word'BARK
& can-make-word'BOOK
& can-make-word'TREAT
& can-make-word'COMMON
& can-make-word'SQUAD
& can-make-word'CONFUSE
);
Output:
A yes
BARK yes
BOOK no
TREAT yes
COMMON no
SQUAD yes
CONFUSE yes

C[edit]

Recursive solution. Empty string returns true.

#include <stdio.h>
#include <ctype.h>

int can_make_words(char **b, char *word)
{
	int i, ret = 0, c = toupper(*word);

#define SWAP(a, b) if (a != b) { char * tmp = a; a = b; b = tmp; }

	if (!c) return 1;
	if (!b[0]) return 0;

	for (i = 0; b[i] && !ret; i++) {
		if (b[i][0] != c && b[i][1] != c) continue;
		SWAP(b[i], b[0]);
		ret = can_make_words(b + 1, word + 1);
		SWAP(b[i], b[0]);
	}

	return ret;
}

int main(void)
{
	char* blocks[] = {
		"BO", "XK", "DQ", "CP", "NA", 
		"GT", "RE", "TG", "QD", "FS", 
		"JW", "HU", "VI", "AN", "OB", 
		"ER", "FS", "LY", "PC", "ZM",
		0 };

	char *words[] = {
		"", "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "Confuse", 0
	};

	char **w;
	for (w = words; *w; w++)
		printf("%s\t%d\n", *w, can_make_words(blocks, *w));

	return 0;
}
Output:
        1
A       1
BARK    1
BOOK    0
TREAT   1
COMMON  0
SQUAD   1
Confuse 1

C#[edit]

Regex[edit]

This Method uses regular expressions to do the checking. Given that n = length of blocks string and m = length of word string, then CheckWord's time complexity comes out to about m*(n - (m-1)/2).

using System;
using System.IO;
// Needed for the method.
using System.Text.RegularExpressions;
using System.Collections.Generic;

void Main()
{
   string blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";
   List<string> words = new List<string>() {
      "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"
   };

   foreach(var word in words)
   {
      Console.WriteLine("{0}: {1}", word, CheckWord(blocks, word));
   }
}

bool CheckWord(string blocks, string word)
{
   for(int i = 0; i < word.Length; ++i)
   {
      int length = blocks.Length;
      Regex rgx = new Regex("([a-z]"+word[i]+"|"+word[i]+"[a-z])", RegexOptions.IgnoreCase);
      blocks = rgx.Replace(blocks, "", 1);
      if(blocks.Length == length) return false;
   }
   return true;
}
Output:
A: True
BARK: True
BOOK: False
TREAT: True
COMMON: False
SQUAD: True
CONFUSE: True

Unoptimized

using System.Collections.Generic;
using System.Linq;

void Main()
{
	List<string> blocks =
	new List<string>() { "bo", "xk", "dq", "cp", "na", "gt", "re", "tg", "qd", "fs",
		"jw", "hu", "vi", "an", "ob", "er", "fs", "ly", "pc", "zm" };
	List<string> words = new List<string>() {
		"A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"};
	
	var solver = new ABC(blocks);
	
	foreach( var word in words)
	{
		Console.WriteLine("{0} :{1}", word, solver.CanMake(word));
	}
}

class ABC
{
	readonly Dictionary<char, List<int>> _blockDict = new Dictionary<char, List<int>>();
	bool[] _used;
	int _nextBlock;

	readonly List<string> _blocks;

	private void AddBlockChar(char c)
	{
		if (!_blockDict.ContainsKey(c))
		{
			_blockDict[c] = new List<int>();
		}
		_blockDict[c].Add(_nextBlock);
	}

	private void AddBlock(string block)
	{
		AddBlockChar(block[0]);
		AddBlockChar(block[1]);
		_nextBlock++;
	}

	public ABC(List<string> blocks)
	{
		_blocks = blocks;
		foreach (var block in blocks)
		{
			AddBlock(block);
		}
	}

	public bool CanMake(string word)
	{
		word = word.ToLower();
		if (word.Length > _blockDict.Count)
		{
			return false;
		}
		_used = new bool[_blocks.Count];
		return TryMake(word);
	}

	public bool TryMake(string word)
	{
		if (word == string.Empty)
		{
			return true;
		}
		var blocks = _blockDict[word[0]].Where(b => !_used[b]);
		foreach (var block in blocks)
		{
			_used[block] = true;
			if (TryMake(word.Substring(1)))
			{
				return true;
			}
			_used[block] = false;
		}
		return false;
	}
}
Output:
A :True
BARK :True
BOOK :False
TREAT :True
COMMON :False
SQUAD :True
CONFUSE :True

C++[edit]

Works with: C++11

Build with:

g++-4.7 -Wall -std=c++0x abc.cpp
#include <iostream>
#include <vector>
#include <string>
#include <set>
#include <cctype>

typedef std::pair<char,char> item_t;
typedef std::vector<item_t> list_t;

bool can_make_word(const std::string& w, const list_t& vals) {
    std::set<uint32_t> used;
    while (used.size() < w.size()) {
        const char c = toupper(w[used.size()]);
        uint32_t x = used.size();
        for (uint32_t i = 0, ii = vals.size(); i < ii; ++i) {
            if (used.find(i) == used.end()) {
                if (toupper(vals[i].first) == c || toupper(vals[i].second) == c) {
                    used.insert(i);
                    break;
                }
            }
        }
        if (x == used.size()) break;
    }
    return used.size() == w.size();
}

int main() {
    list_t vals{ {'B','O'}, {'X','K'}, {'D','Q'}, {'C','P'}, {'N','A'}, {'G','T'}, {'R','E'}, {'T','G'}, {'Q','D'}, {'F','S'}, {'J','W'}, {'H','U'}, {'V','I'}, {'A','N'}, {'O','B'}, {'E','R'}, {'F','S'}, {'L','Y'}, {'P','C'}, {'Z','M'} };
    std::vector<std::string> words{"A","BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE"};
    for (const std::string& w : words) {
        std::cout << w << ": " << std::boolalpha << can_make_word(w,vals) << ".\n";
    }
}
Output:
A: true.
BARK: true.
BOOK: false.
TREAT: true.
COMMON: false.
SQUAD: true.
CONFUSE: true.

Ceylon[edit]

Functional programming/recursive solution. No variable values.

module.ceylon

module rosetta.abc "1.0.0" {}

run.ceylon

shared void run() {
    printAndCanMakeWord("A", blocks);
    //True
    printAndCanMakeWord("BARK", blocks);
    //True
    printAndCanMakeWord("BOOK", blocks);
    //False
    printAndCanMakeWord("TREAT", blocks);
    //True
    printAndCanMakeWord("COMMON", blocks);
    //False
    printAndCanMakeWord("SQUAD", blocks);
    //True
    printAndCanMakeWord("CONFUSE", blocks);
    //True
}

Block[] blocks =
    [
        Block('B','O'),
        Block('X','K'),
        Block('D','Q'),
        Block('C','P'),
        Block('N','A'),
        Block('G','T'),
        Block('R','E'),
        Block('T','G'),
        Block('Q','D'),
        Block('F','S'),
        Block('J','W'),
        Block('H','U'),
        Block('V','I'),
        Block('A','N'),
        Block('O','B'),
        Block('E','R'),
        Block('F','S'),
        Block('L','Y'),
        Block('P','C'),
        Block('Z','M')
    ];

void printAndCanMakeWord(String word, Block[] blocks) {
    print("``word``:``canMakeWord(word, blocks)``");
}

class Block(Character firstLetter, Character secondLetter) {
    shared Character firstLetterUpper = firstLetter.uppercased;
    shared Character secondLetterUpper = secondLetter.uppercased;

    shared Boolean containsLetter(Character letter)
        => let (letterUpper = letter.uppercased)
            firstLetterUpper == letterUpper || secondLetterUpper == letterUpper;

    shared actual String string = "``firstLetterUpper``,``secondLetterUpper``";
}

Boolean canMakeWord(String word, Block[] blocks)
    => canMakeWordRecursive(word.uppercased.sequence(), 0, blocks, word.indexes());

Boolean canMakeWordRecursive(Character[] word,
                             Integer index,
                             Block[] remainingBlocks,
                             Integer[] remainingLetterIndexes)
    => if (exists wordFirst = word.first, // first is the Ceylon attribute for head
           exists remainingBlock = remainingBlocks.find((remainingBlock) => remainingBlock.containsLetter(wordFirst)))
        then
            let (myRemainingLetterIndexes = remainingLetterIndexes.filter((theIndex) => index != theIndex).sequence())
             if (myRemainingLetterIndexes.empty)
                 then true
                 else canMakeWordRecursive(word.rest,// rest is the Ceylon attribute for tail
                                           index+1, // move through the letter indexes
                                           remainingBlocks.filter((block) => remainingBlock != block).sequence(), // one less block
                                           myRemainingLetterIndexes)
        else false;
Output:
A:true
BARK:true
BOOK:false
TREAT:true
COMMON:false
SQUAD:true
CONFUSE:true

Clojure[edit]

A translation of the Haskell solution.

(def blocks
  (-> "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM" (.split " ") vec))

(defn omit 
  "return bs with (one instance of) b omitted"
  [bs b] 
  (let [[before after] (split-with #(not= b %) bs)]
    (concat before (rest after))))

(defn abc 
  "return lazy sequence of solutions (i.e. block lists)"
  [blocks [c & cs]]
  (if (some? c)
    (for [b blocks :when (some #(= c %) b)
          bs (abc (omit blocks b) cs)]
      (cons b bs))
    [[]]))
    
      
(doseq [word ["A" "BARK" "Book" "treat" "COMMON" "SQUAD" "CONFUSE"]]
  (->> word .toUpperCase (abc blocks) first (printf "%s: %b\n" word)))
Output:
A: true
BARK: true
Book: false
treat: true
COMMON: false
SQUAD: true
CONFUSE: true

CLU[edit]

ucase = proc (s: string) returns (string)
    rslt: array[char] := array[char]$predict(1,string$size(s))
    for c: char in string$chars(s) do   
        if c>='a' & c<='z' then
            c := char$i2c(char$c2i(c) - 32)
        end
        array[char]$addh(rslt,c)
    end
    return(string$ac2s(rslt))
end ucase

abc = proc (s: string) returns (bool)
    own collection: sequence[string] := sequence[string]$
      ["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
       "JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"]
    
    blocks: array[string] := sequence[string]$s2a(collection)
    for c: char in string$chars(ucase(s)) do
        begin
            for i: int in array[string]$indexes(blocks) do
                if string$indexc(c, blocks[i]) ~= 0 then
                    blocks[i] := ""
                    exit found
                end
            end
            return(false)
        end
        except when found: end
    end
    return(true)
end abc

start_up = proc ()
    po: stream := stream$primary_output()
    words: sequence[string] := sequence[string]$
        ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"]
    
    for word: string in sequence[string]$elements(words) do
        stream$puts(po, word || ": ")
        if abc(word) then stream$putl(po, "yes")
        else stream$putl(po, "no")
        end
    end
end start_up
Output:
A: yes
BARK: yes
BOOK: no
TREAT: yes
COMMON: no
SQUAD: yes
CONFUSE: yes

CoffeeScript[edit]

blockList = [ 'BO', 'XK', 'DQ', 'CP', 'NA', 'GT', 'RE', 'TG', 'QD', 'FS', 'JW', 'HU', 'VI', 'AN', 'OB', 'ER', 'FS', 'LY', 'PC', 'ZM' ]

canMakeWord = (word="") ->
    # Create a shallow clone of the master blockList
    blocks = blockList.slice 0
    # Check if blocks contains letter
    checkBlocks = (letter) ->
        # Loop through every remaining block
        for block, idx in blocks
            # If letter is in block, blocks.splice will return an array, which will evaluate as true
            return blocks.splice idx, 1 if letter.toUpperCase() in block
        false
    # Return true if there are no falsy values
    false not in (checkBlocks letter for letter in word)

# Expect true, true, false, true, false, true, true, true
for word in ["A", "BARK", "BOOK", "TREAT", "COMMON", "squad", "CONFUSE", "STORM"]
    console.log word + " -> " + canMakeWord(word)
Output:
A -> true
BARK -> true
BOOK -> false
TREAT -> true
COMMON -> false
squad -> true
CONFUSE -> true
STORM -> true

Comal[edit]

0010 FUNC can'make'word#(word$) CLOSED
0020   blocks$:=" BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
0030   FOR i#:=1 TO LEN(word$) DO
0040     pos#:=UPPER$(word$(i#)) IN blocks$
0050     IF NOT pos# THEN RETURN FALSE
0060     blocks$(pos#):="";blocks$(pos# BITXOR 1):=""
0070   ENDFOR i#
0080   RETURN TRUE
0090 ENDFUNC
0100 //
0110 DIM yesno$(0:1) OF 3
0120 yesno$(FALSE):="no";yesno$(TRUE):="yes"
0130 WHILE NOT EOD DO
0140   READ w$
0150   PRINT w$,": ",yesno$(can'make'word#(w$))
0160 ENDWHILE
0170 END
0180 //
0190 DATA "A","BARK","BOOK","treat","common","squad","CoNfUsE"
Output:
A: yes
BARK: yes
BOOK: no
treat: yes
common: no
squad: yes
CoNfUsE: yes

Common Lisp[edit]

(defun word-possible-p (word blocks)
  (cond 
    ((= (length word) 0) t)
    ((null blocks) nil)
    (t (let* 
         ((c (aref word 0))
          (bs (remove-if-not #'(lambda (b) 
                                 (find c b :test #'char-equal))
                             blocks)))
         (some #'identity 
               (loop for b in bs
                     collect (word-possible-p
                               (subseq word 1)
                               (remove b blocks))))))))
Output:
> (defparameter *blocks* 
    '("BO" "XK" "DQ" "CP" "NA" "GT" "RE" "TG" "QD" "FS" 
      "JW" "HU" "VI" "AN" "OB" "ER" "FS" "LY" "PC" "ZM"))
> (dolist (w '("" "A" "bArk" "BOOK" "trEAt" "CoMmoN" "squad" "conFUse"))
    (format t "~s is possible: ~a~%" w (word-possible-p w *blocks*)))
"" is possible: T
"A" is possible: T
"bArk" is possible: T
"BOOK" is possible: NIL
"trEAt" is possible: T
"CoMmoN" is possible: NIL
"squad" is possible: T
"conFUse" is possible: T
NIL
> (word-possible-p "abba" '("AB" "AB" "AC" "AC"))
T

Component Pascal[edit]

MODULE ABCProblem;
IMPORT
	StdLog, DevCommanders, TextMappers;
CONST
	notfound = -1;
TYPE	
	String = ARRAY 3 OF CHAR;
VAR
	blocks : ARRAY 20 OF String;
	
PROCEDURE Check(s: ARRAY OF CHAR): BOOLEAN;
VAR
	used: SET;
	i,blockIndex: INTEGER;
	
	PROCEDURE GetBlockFor(c: CHAR): INTEGER;
	VAR
		i: INTEGER;
	BEGIN
		c := CAP(c);
		i := 0;
		WHILE (i < LEN(blocks)) DO
			IF (c = blocks[i][0]) OR (c = blocks[i][1]) THEN
				IF ~(i IN used) THEN RETURN i END
			END;
			INC(i)
		END;
		RETURN notfound
	END GetBlockFor;
	
BEGIN
	used := {};
	FOR i := 0 TO LEN(s$) - 1 DO
		blockIndex := GetBlockFor(s[i]);
		IF blockIndex = notfound THEN 
			RETURN FALSE
		ELSE
			INCL(used,blockIndex)
		END
	END;
	RETURN TRUE
END Check;	

PROCEDURE CanMakeWord*;
VAR
	s: TextMappers.Scanner;
BEGIN
	s.ConnectTo(DevCommanders.par.text);
	s.SetPos(DevCommanders.par.beg);
	s.Scan;
	WHILE (~s.rider.eot) DO
		IF (s.type = TextMappers.char) & (s.char = '~') THEN
			RETURN
		ELSIF (s.type = TextMappers.string) THEN
			StdLog.String(s.string);StdLog.String(":> ");
			StdLog.Bool(Check(s.string));StdLog.Ln
		END;
		s.Scan
	END
END CanMakeWord;

BEGIN
	blocks[0] := "BO";
	blocks[1] := "XK";
	blocks[2] := "DQ";
	blocks[3] := "CP";
	blocks[4] := "NA";
	blocks[5] := "GT";
	blocks[6] := "RE";
	blocks[7] := "TG";
	blocks[8] := "QD";
	blocks[9] := "FS";
	blocks[10] := "JW";
	blocks[11] := "HU";
	blocks[12] := "VI";
	blocks[13] := "AN";
	blocks[14] := "OB";
	blocks[15] := "ER";
	blocks[16] := "FS";
	blocks[17] := "LY";
	blocks[18] := "PC";
	blocks[19] := "ZM";
	
END ABCProblem.

Execute: ^Q ABCProblem.CanMakeWord A BARK BOOK TREAT COMMON SQUAD confuse~

Output:
A:>  $TRUE
BARK:>  $TRUE
BOOK:>  $FALSE
TREAT:>  $TRUE
COMMON:>  $FALSE
SQUAD:>  $TRUE
confuse:>  $TRUE

Cowgol[edit]

include "cowgol.coh";
include "strings.coh";

sub can_make_word(word: [uint8]): (r: uint8) is
    var blocks: [uint8] := "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM";
    
    # Initialize blocks array
    var avl: uint8[41];
    CopyString(blocks, &avl[0]);
    
    r := 1;
    loop
        var letter := [word];
        word := @next word;
        if letter == 0 then break; end if;
        
        # find current letter in blocks
        var i: @indexof avl := 0;
        loop    
            var block := avl[i];
            if block == 0 then
                # no block, this word cannot be formed
                r := 0;
                return;
            elseif block == letter then
                # we found it, blank it out
                avl[i] := ' ';
                avl[i^1] := ' '; # and the other letter on the block too
                break;
            end if;
            i := i + 1;
        end loop;
    end loop;
end sub;

# test a list of words
var words: [uint8][] := {"A","BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE"};
var resp: [uint8][] := {": No\n", ": Yes\n"};
var i: @indexof words := 0;
while i < @sizeof words loop
    print(words[i]);
    print(resp[can_make_word(words[i])]);
    i := i + 1;
end loop;
Output:
A: Yes
BARK: Yes
BOOK: No
TREAT: Yes
COMMON: No
SQUAD: Yes
CONFUSE: Yes

D[edit]

Basic Version[edit]

Translation of: Python

A simple greedy algorithm is enough for the given sequence of blocks. canMakeWord is true on an empty word because you can compose it using zero blocks.

import std.stdio, std.algorithm, std.string;

bool canMakeWord(in string word, in string[] blocks) pure /*nothrow*/ @safe {
    auto bs = blocks.dup;
    outer: foreach (immutable ch; word.toUpper) {
        foreach (immutable block; bs)
            if (block.canFind(ch)) {
                bs = bs.remove(bs.countUntil(block));
                continue outer;
            }
        return false;
    }
    return true;
}

void main() @safe {
    immutable blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI
                        AN OB ER FS LY PC ZM".split;

    foreach (word; "" ~ "A BARK BoOK TrEAT COmMoN SQUAD conFUsE".split)
        writefln(`"%s" %s`, word, canMakeWord(word, blocks));
}
Output:
"" true
"A" true
"BARK" true
"BoOK" false
"TrEAT" true
"COmMoN" false
"SQUAD" true
"conFUsE" true

@nogc Version[edit]

The same as the precedent version, but it avoids all heap allocations and it's lower-level and ASCII-only.

import std.ascii, core.stdc.stdlib;

bool canMakeWord(in string word, in string[] blocks) nothrow @nogc
in {
    foreach (immutable char ch; word)
        assert(ch.isASCII);
    foreach (const block; blocks)
        assert(block.length == 2 && block[0].isASCII && block[1].isASCII);
} body {
    auto ptr = cast(string*)alloca(blocks.length * string.sizeof);
    if (ptr == null)
        exit(1);
    auto blocks2 = ptr[0 .. blocks.length];
    blocks2[] = blocks[];

    outer: foreach (immutable i; 0 .. word.length) {
        immutable ch = word[i].toUpper;
        foreach (immutable j; 0 .. blocks2.length) {
            if (blocks2[j][0] == ch || blocks2[j][1] == ch) {
                if (blocks2.length > 1)
                    blocks2[j] = blocks2[$ - 1];
                blocks2 = blocks2[0 .. $ - 1];
                continue outer;
            }
        }
        return false;
    }
    return true;
}

void main() {
    import std.stdio, std.string;

    immutable blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI
                        AN OB ER FS LY PC ZM".split;

    foreach (word; "" ~ "A BARK BoOK TrEAT COmMoN SQUAD conFUsE".split)
        writefln(`"%s" %s`, word, canMakeWord(word, blocks));
}

Recursive Version[edit]

This version is able to find the solution for the word "abba" given the blocks AB AB AC AC.

Translation of: C
import std.stdio, std.ascii, std.algorithm, std.array;

alias Block = char[2];

// Modifies the order of the given blocks.
bool canMakeWord(Block[] blocks, in string word) pure nothrow
in {
    assert(blocks.all!(w => w[].all!isAlpha));
    assert(word.all!isAlpha);
} body {
    if (word.empty)
        return true;

    immutable c = word[0].toUpper;
    foreach (ref b; blocks) {
        if (b[0].toUpper != c && b[1].toUpper != c)
            continue;
        blocks[0].swap(b);
        if (blocks[1 .. $].canMakeWord(word[1 .. $]))
            return true;
        blocks[0].swap(b);
    }

    return false;
}

void main() {
    enum Block[] blocks = "BO XK DQ CP NA GT RE TG QD FS
                           JW HU VI AN OB ER FS LY PC ZM".split;

    foreach (w; "" ~ "A BARK BoOK TrEAT COmMoN SQUAD conFUsE".split)
        writefln(`"%s" %s`, w, blocks.canMakeWord(w));

    // Extra test.
    Block[] blocks2 = ["AB", "AB", "AC", "AC"];
    immutable word = "abba";
    writefln(`"%s" %s`, word, blocks2.canMakeWord(word));
}
Output:
"" true
"A" true
"BARK" true
"BoOK" false
"TrEAT" true
"COmMoN" false
"SQUAD" true
"conFUsE" true
"abba" true

Alternative Recursive Version[edit]

This version doesn't shuffle the input blocks, but it's more complex and it allocates an array of indexes.

import std.stdio, std.ascii, std.algorithm, std.array, std.range;

alias Block = char[2];

bool canMakeWord(immutable Block[] blocks, in string word) pure nothrow
in {
    assert(blocks.all!(w => w[].all!isAlpha));
    assert(word.all!isAlpha);
} body {
    bool inner(size_t[] indexes, in string w) pure nothrow {
        if (w.empty)
            return true;

        immutable c = w[0].toUpper;
        foreach (ref idx; indexes) {
            if (blocks[idx][0].toUpper != c &&
                blocks[idx][1].toUpper != c)
                continue;
            indexes[0].swap(idx);
            if (inner(indexes[1 .. $], w[1 .. $]))
                return true;
            indexes[0].swap(idx);
        }

        return false;
    }

    return inner(blocks.length.iota.array, word);
}

void main() {
    enum Block[] blocks = "BO XK DQ CP NA GT RE TG QD FS
                           JW HU VI AN OB ER FS LY PC ZM".split;

    foreach (w; "" ~ "A BARK BoOK TrEAT COmMoN SQUAD conFUsE".split)
        writefln(`"%s" %s`, w, blocks.canMakeWord(w));

    // Extra test.
    immutable Block[] blocks2 = ["AB", "AB", "AC", "AC"];
    immutable word = "abba";
    writefln(`"%s" %s`, word, blocks2.canMakeWord(word));
}

The output is the same.

Delphi[edit]

Just to be different I implemented a block as a set of (2) char rather than as an array of (2) char.

program ABC;
{$APPTYPE CONSOLE}

uses SysUtils;

type
  TBlock = set of char;

const
  TheBlocks : array [0..19] of TBlock =
  (
    [ 'B', 'O' ],    [ 'X', 'K' ],    [ 'D', 'Q' ],    [ 'C', 'P' ],    [ 'N', 'A' ],
    [ 'G', 'T' ],    [ 'R', 'E' ],    [ 'T', 'G' ],    [ 'Q', 'D' ],    [ 'F', 'S' ],
    [ 'J', 'W' ],    [ 'H', 'U' ],    [ 'V', 'I' ],    [ 'A', 'N' ],    [ 'O', 'B' ],
    [ 'E', 'R' ],    [ 'F', 'S' ],    [ 'L', 'Y' ],    [ 'P', 'C' ],    [ 'Z', 'M' ]
  );

function SolveABC(Target : string; Blocks : array of TBlock) : boolean;
var
  iChr : integer;
  Used : array [0..19] of boolean;

  function FindUnused(TargetChr : char) : boolean;  // Nested routine
  var
    iBlock : integer;
  begin
    Result := FALSE;
    for iBlock := low(Blocks) to high(Blocks) do
      if (not Used[iBlock]) and ( TargetChr in Blocks[iBlock] ) then
      begin
        Result := TRUE;
        Used[iBlock] := TRUE;
        Break;
      end;
  end;

begin
  FillChar(Used, sizeof(Used), ord(FALSE));
  Result := TRUE;
  iChr := 1;
  while Result and (iChr <= length(Target)) do
    if FindUnused(Target[iChr]) then inc(iChr)
                                else Result := FALSE;
end;

procedure CheckABC(Target : string);
begin
  if SolveABC(uppercase(Target), TheBlocks) then
    writeln('Can make ' + Target)
  else
    writeln('Can NOT make ' + Target);
end;

begin
  CheckABC('A');
  CheckABC('BARK');
  CheckABC('BOOK');
  CheckABC('TREAT');
  CheckABC('COMMON');
  CheckABC('SQUAD');
  CheckABC('CONFUSE');
  readln;
end.
Output:
Output:
Can make A
Can make BARK
Can NOT make BOOK
Can make TREAT
Can NOT make COMMON
Can make SQUAD
Can make CONFUSE

Draco[edit]

\util.g

proc nonrec ucase(char c) char:
    byte b;
    b := pretend(c, byte);
    b := b & ~32;
    pretend(b, char)
corp 

proc nonrec can_make_word(*char w) bool:
    [41] char blocks;
    word i;
    char ch;
    bool found, ok;
    
    CharsCopy(&blocks[0], "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM");
    
    ok := true;
    while 
        ch := ucase(w*); 
        w := w + 1;
        ok and ch ~= '\e'
    do
        found := false;
        i := 0;
        while not found and i < 40 do
            if blocks[i] = ch then found := true fi;
            i := i + 1;
        od;
        if found then
            i := i - 1;
            blocks[i] := '\e';
            blocks[i >< 1] := '\e'
        else    
            ok := false
        fi
    od;
    ok
corp

proc nonrec test(*char w) void:
    writeln(w, ": ", if can_make_word(w) then "yes" else "no" fi)
corp

proc nonrec main() void:
    test("A");
    test("BARK");
    test("book");
    test("treat");
    test("CoMmOn");
    test("sQuAd");
    test("CONFUSE")
corp
Output:
A: yes
BARK: yes
book: no
treat: yes
CoMmOn: no
sQuAd: yes
CONFUSE: yes

Dyalect[edit]

Translation of: Swift
func blockable(str) {
    var blocks = [
        "BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
        "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM" ]
 
    var strUp = str.Upper()
    var fin = ""
 
    for c in strUp {
        for j in blocks.Indices() {
            if blocks[j].StartsWith(c) || blocks[j].EndsWith(c) {
                fin += c
                blocks[j] = ""
                break
            }
        }
    }
 
    return fin == strUp
}
 
func canOrNot(can) => can ? "can" : "cannot"
 
for str in [ "A", "BARK", "BooK", "TrEaT", "comMON", "sQuAd", "Confuse" ] {
    print("\"\(str)\" \(canOrNot(blockable(str))) be spelled with blocks.")
}
Output:
"A" can be spelled with blocks.
"BARK" can be spelled with blocks.
"BooK" cannot be spelled with blocks.
"TrEaT" can be spelled with blocks.
"comMON" cannot be spelled with blocks.
"sQuAd" can be spelled with blocks.
"Confuse" can be spelled with blocks.

EchoLisp[edit]

(lib 'list) ;; list-delete

(define BLOCKS '("BO" "XK" "DQ" "CP" "NA" "GT" "RE" "TG" "QD" "FS" 
	     "JW" "HU" "VI" "AN" "OB" "ER" "FS" "LY" "PC" "ZM" ))
	     
(define WORDS '("A" "BARK" "BOOK" "TREAT" "COMMON" "SQUAD" "CONFUSE"))
	     
(define (spell word blocks)
    (cond
	((string-empty? word) #t)
	((empty? blocks) #f)
	(else
	(for/or [(block blocks)]
		#:continue (not (string-match block (string-first word)))
		(spell (string-rest word) (list-delete blocks block))))))
Output:
(for ((w WORDS)) 
  (writeln 
    (string-randcase w) 
    (spell (string-upcase w) BLOCKS)))
	
A     #t    
bARK     #t    
BooK     #f    
TReAt     #t    
ComMOn     #f    
sqUAd     #t    
COnfUSe     #t  

Ela[edit]

Translation of: Haskell
open list monad io char

:::IO

null = foldr (\_ _ -> false) true

mapM_ f = foldr ((>>-) << f) (return ())

abc _ [] = [[]]
abc blocks (c::cs) = 
  [b::ans \\ b <- blocks | c `elem` b, ans <- abc (delete b blocks) cs]

blocks = ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
          "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"]

mapM_ (\w -> putLn (w, not << null $ abc blocks (map char.upper w)))
  ["", "A", "BARK", "BoOK", "TrEAT", "COmMoN", "SQUAD", "conFUsE"]
Output:
("conFUsE",true)
("SQUAD",true)
("COmMoN",false)
("TrEAT",true)
("BoOK",false)
("BARK",true)
("A",true)
("",true)

Elena[edit]

ELENA 5.0

import system'routines;
import system'collections;
import extensions;
import extensions'routines;
 
extension op
{
    canMakeWordFrom(blocks)
    {
        var list := ArrayList.load(blocks);
 
        ^ nil == (cast string(self)).upperCase().seekEach:(ch)
        {
            var index := list.indexOfElement
                ((word => word.indexOf(0, ch) != -1).asComparator());
 
            if (index>=0)
            {
                list.removeAt(index); ^ false
            }
            else
            {
                ^ true
            }
        }
    }
}
 
public program()
{
    var blocks := new string[]{"BO", "XK", "DQ", "CP", "NA", 
		"GT", "RE", "TG", "QD", "FS", 
		"JW", "HU", "VI", "AN", "OB", 
		"ER", "FS", "LY", "PC", "ZM"};
 
    var words := new string[]{"", "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "Confuse"};
 
    Enumerator e := words.enumerator();
    e.next();
 
    words.forEach:(word)
    {
        console.printLine("can make '",word,"' : ",word.canMakeWordFrom(blocks));
    }
}
Output:
can make '' : true
can make 'A' : true
can make 'BARK' : true
can make 'BOOK' : false
can make 'TREAT' : true
can make 'COMMON' : false
can make 'SQUAD' : true
can make 'Confuse' : true

Elixir[edit]

Translation of: Erlang
Works with: Elixir version 1.3
defmodule ABC do
  def can_make_word(word, avail) do
    can_make_word(String.upcase(word) |> to_charlist, avail, [])
  end
  
  defp can_make_word([], _, _), do: true
  defp can_make_word(_, [], _), do: false
  defp can_make_word([l|tail], [b|rest], tried) do 
    (l in b and can_make_word(tail, rest++tried, []))
    or can_make_word([l|tail], rest, [b|tried])
  end
end

blocks = ~w(BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM)c
~w(A Bark Book Treat Common Squad Confuse) |>
Enum.map(fn(w) -> IO.puts "#{w}: #{ABC.can_make_word(w, blocks)}" end)
Output:
A: true
Bark: true
Book: false
Treat: true
Common: false
Squad: true
Confuse: true

Erlang[edit]

-module(abc).
-export([can_make_word/1, can_make_word/2, blocks/0]).

blocks() -> ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", 
             "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"].

can_make_word(Word) -> can_make_word(Word, blocks()).
can_make_word(Word, Avail) -> can_make_word(string:to_upper(Word), Avail, []).
can_make_word([], _, _) -> true;
can_make_word(_, [], _) -> false; 
can_make_word([L|Tail], [B|Rest], Tried) -> 
  (lists:member(L,B) andalso can_make_word(Tail, lists:append(Rest, Tried),[])) 
  orelse can_make_word([L|Tail], Rest, [B|Tried]).

main(_) -> lists:map(fun(W) -> io:fwrite("~s: ~s~n", [W, can_make_word(W)]) end,
                     ["A","Bark","Book","Treat","Common","Squad","Confuse"]).
Output:
A: true
Bark: true
Book: false
Treat: true
Common: false
Squad: true
Confuse: true

ERRE[edit]

PROGRAM BLOCKS

!$INCLUDE="PC.LIB"

PROCEDURE CANMAKEWORD(WORD$)
   LOCAL B$,P%
   B$=BLOCKS$
   PRINT(WORD$;" -> ";)
   P%=INSTR(B$,CHR$(ASC(WORD$) AND $DF))
   WHILE P%>0 AND WORD$>"" DO
      CHANGE(B$,P%-1+(P% MOD 2),".."->B$)
      WORD$=MID$(WORD$,2)
      EXIT IF WORD$=""
      P%=INSTR(B$,CHR$(ASC(WORD$) AND $DF))
   END WHILE
   IF WORD$>"" THEN PRINT("False") ELSE PRINT("True") END IF
END PROCEDURE

BEGIN
  BLOCKS$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
  CANMAKEWORD("A")
  CANMAKEWORD("BARK")
  CANMAKEWORD("BOOK")
  CANMAKEWORD("TREAT")
  CANMAKEWORD("COMMON")
  CANMAKEWORD("SQUAD")
  CANMAKEWORD("Confuse")
END PROGRAM

Euphoria[edit]

implemented using OpenEuphoria

include std/text.e

sequence blocks = {{'B','O'},{'X','K'},{'D','Q'},{'C','P'},{'N','A'},
                   {'G','T'},{'R','E'},{'T','G'},{'Q','D'},{'F','S'},
                   {'J','W'},{'H','U'},{'V','I'},{'A','N'},{'O','B'},
                   {'E','R'},{'F','S'},{'L','Y'},{'P','C'},{'Z','M'}}
sequence words = {"A","BarK","BOOK","TrEaT","COMMON","SQUAD","CONFUSE"}

sequence current_word
sequence temp 
integer matches

for i = 1 to length(words) do
	current_word = upper(words[i])
	temp = blocks
	matches = 0
	for j = 1 to length(current_word) do
		for k = 1 to length(temp) do
			if find(current_word[j],temp[k]) then
				temp = remove(temp,k) 
				matches += 1
				exit
			end if
		end for
		if length(current_word) = matches then
			printf(1,"%s: TRUE\n",{words[i]})
			exit
		end if
	end for
	if length(current_word) != matches then
		printf(1,"%s: FALSE\n",{words[i]})
	end if
end for

if getc(0) then end if
Output:
A: TRUE
BarK: TRUE
BOOK: FALSE
TrEaT: TRUE
COMMON: FALSE
SQUAD: TRUE
CONFUSE: TRUE

..press Enter..

F#[edit]

This solution does not depend on the order of the blocks, neither on the symmetry of blocks we see in the example block set. (Symmetry: if AB is a block, an A comes only with another AB|BA)

let rec spell_word_with blocks w =
    let rec look_for_right_candidate candidates noCandidates c rest =
        match candidates with
        | [] -> false
        | c0::cc -> 
            if spell_word_with (cc@noCandidates) rest then true
            else look_for_right_candidate cc (c0::noCandidates) c rest

    match w with
    | "" -> true
    | w ->
        let c = w.[0]
        let rest = w.Substring(1)
        let (candidates, noCandidates) = List.partition(fun (c1,c2) -> c = c1 || c = c2) blocks
        look_for_right_candidate candidates noCandidates c rest

[<EntryPoint>]
let main argv =
    let default_blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
    let blocks =
        (if argv.Length > 0 then argv.[0] else default_blocks).Split()
        |> List.ofArray
        |> List.map(fun s -> s.ToUpper())
        |> List.map(fun s2 -> s2.[0], s2.[1])
    let words =
        (if argv.Length > 0 then List.ofArray(argv).Tail else [])
        |> List.map(fun s -> s.ToUpper())

    List.iter (fun w -> printfn "Using the blocks we can make the word '%s': %b" w (spell_word_with blocks w)) words
    0
Output:
h:\RosettaCode\ABC\Fsharp>RosettaCode "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM" a bark book threat common squad confuse
Using the blocks we can make the word 'A': true
Using the blocks we can make the word 'BARK': true
Using the blocks we can make the word 'BOOK': false
Using the blocks we can make the word 'THREAT': true
Using the blocks we can make the word 'COMMON': false
Using the blocks we can make the word 'SQUAD': true
Using the blocks we can make the word 'CONFUSE': true

h:\RosettaCode\ABC\Fsharp>RosettaCode  "aB aB Ac Ac" abba
Using the blocks we can make the word 'ABBA': true

h:\RosettaCode\ABC\Fsharp>RosettaCode "US TZ AO QA" Auto
Using the blocks we can make the word 'AUTO': true

Factor[edit]

USING: assocs combinators.short-circuit formatting grouping io
kernel math math.statistics qw sequences sets unicode ;
IN: rosetta-code.abc-problem

! === CONSTANTS ================================================

CONSTANT: blocks qw{
    BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
}

CONSTANT: input qw{ A BARK BOOK TREAT COMMON SQUAD CONFUSE }

! === PROGRAM LOGIC ============================================

: pare ( str -- seq )
    [ blocks ] dip [ intersects? ] curry filter ;

: enough-blocks? ( str -- ? ) dup pare [ length ] bi@ <= ;

: enough-letters? ( str -- ? )
    [ blocks concat ] dip dup [ within ] dip
    [ histogram values ] bi@ [ - ] 2map [ neg? ] any? not ;

: can-make-word? ( str -- ? )
    >upper { [ enough-blocks? ] [ enough-letters? ] } 1&& ;

! === OUTPUT ===================================================

: show-blocks ( -- )
    "Available blocks:" print blocks [ 1 cut "(%s %s)" sprintf ]
    map 5 group [ [ write bl ] each nl ] each nl ;

: header ( -- )
    "Word" "Can make word from blocks?" "%-7s %s\n" printf
    "======= ==========================" print ;

: result ( str -- )
    dup can-make-word? "Yes" "No" ? "%-7s %s\n" printf ;

! === MAIN =====================================================

: abc-problem ( -- )
    show-blocks header input [ result ] each ;

MAIN: abc-problem
Output:
Available blocks:
(B O) (X K) (D Q) (C P) (N A) 
(G T) (R E) (T G) (Q D) (F S) 
(J W) (H U) (V I) (A N) (O B) 
(E R) (F S) (L Y) (P C) (Z M) 

Word    Can make word from blocks?
======= ==========================
A       Yes
BARK    Yes
BOOK    No
TREAT   Yes
COMMON  No
SQUAD   Yes
CONFUSE Yes

FBSL[edit]

This approach uses a string, blanking out the pair previously found. Probably faster than array manipulation.

#APPTYPE CONSOLE
SUB MAIN()
	BlockCheck("A")
	BlockCheck("BARK")
	BlockCheck("BooK")
	BlockCheck("TrEaT")
	BlockCheck("comMON")
	BlockCheck("sQuAd")
	BlockCheck("Confuse")
	pause
END SUB

FUNCTION BlockCheck(str)
	print str " " iif( Blockable( str ), "can", "cannot" ) " be spelled with blocks."
END FUNCTION

FUNCTION Blockable(str AS STRING)
	DIM blocks AS STRING = "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
	DIM C AS STRING = ""
	DIM POS AS INTEGER = 0
	
	FOR DIM I = 1 TO LEN(str)
		C = str{i}
		POS = INSTR(BLOCKS, C, 0, 1) 'case insensitive
		IF POS > 0 THEN
			'if the pos is odd, it's the first of the pair
			IF POS MOD 2 = 1 THEN
				'so clear the first and the second
				poke(@blocks + pos - 1," ")
				poke(@blocks + pos," ")
			'otherwise, it's the last of the pair	
			ELSE
				'clear the second and the first
				poke(@blocks + pos - 1," ")
				poke(@blocks + pos - 2," ")
			END IF
		ELSE
		'not found, so can't be spelled
		RETURN FALSE
		END IF
	NEXT
	'got thru to here, so can be spelled
	RETURN TRUE
END FUNCTION
Output:
A can be spelled with blocks.
BARK can be spelled with blocks.
BooK cannot be spelled with blocks.
TrEaT can be spelled with blocks.
comMON cannot be spelled with blocks.
sQuAd can be spelled with blocks.
Confuse can be spelled with blocks.

Press any key to continue...


Forth[edit]

Works with: gforth version 0.7.3
: blockslist s" BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM" ;
variable blocks
: allotblocks ( -- ) here blockslist dup allot here over - swap move blocks ! ;
: freeblocks blockslist nip negate allot ;
: toupper 223 and ;

: clearblock ( addr-block -- ) 
dup '_' swap c!
dup blocks @ - 1 and if 1- else 1+ then
'_' swap c!
;

: pickblock ( addr-input -- addr-input+1 f )
dup 1+ swap c@ toupper    ( -- addr-input+1 c )
blockslist nip 0 do
  blocks @ i + dup c@ 2 pick       ( -- addr-input+1 c addri ci c )
  = if clearblock drop true unloop exit else drop then
loop drop false
;

: abc ( addr-input u -- f )
allotblocks
0 do
  pickblock
  invert if drop false unloop exit cr then
loop drop true
freeblocks
;

: .abc abc if ." True" else ." False" then ;
Output:
s" A" .abc True ok
s" BarK" .abc True ok
s" BOOK" .abc False ok
s" TrEaT" .abc True ok
s" COMMON" .abc False ok
s" SQUAD" .abc True ok
s" CONFUSE" .abc True ok


Fortran[edit]

Attempts to write the word read from unit 5. Please find the output, bash command, and gfortran compilation instructions as commentary at the start of the source, which starts right away!

!-*- mode: compilation; default-directory: "/tmp/" -*-
!Compilation started at Thu Jun  5 01:52:03
!
!make f && for a in '' a bark book treat common squad confuse ; do echo $a | ./f ; done
!gfortran -std=f2008 -Wall -fopenmp -ffree-form -fall-intrinsics -fimplicit-none -g f.f08 -o f
! T                      
! T  A                    NA
! T  BARK                 BO NA RE XK
! F  BOOK                 OB BO -- --
! T  TREAT                GT RE ER NA TG
! F  COMMON               PC OB ZM -- -- --
! T  SQUAD                FS DQ HU NA QD
! T  CONFUSE              CP BO NA FS HU FS RE
!
!Compilation finished at Thu Jun  5 01:52:03

program abc
  implicit none
  integer, parameter :: nblocks = 20
  character(len=nblocks) :: goal
  integer, dimension(nblocks) :: solution
  character(len=2), dimension(0:nblocks) :: blocks_copy, blocks = &
       &(/'--','BO','XK','DQ','CP','NA','GT','RE','TG','QD','FS','JW','HU','VI','AN','OB','ER','FS','LY','PC','ZM'/)
  logical :: valid
  integer :: i, iostat
  read(5,*,iostat=iostat) goal
  if (iostat .ne. 0) goal = ''
  call ucase(goal)
  solution = 0
  blocks_copy = blocks
  valid = assign_block(goal(1:len_trim(goal)), blocks, solution, 1)
  write(6,*) valid, ' '//goal, (' '//blocks_copy(solution(i)), i=1,len_trim(goal))

contains

  recursive function assign_block(goal, blocks, solution, n) result(valid)
    implicit none
    logical :: valid
    character(len=*), intent(in) :: goal
    character(len=2), dimension(0:), intent(inout) :: blocks
    integer, dimension(:), intent(out) :: solution
    integer, intent(in) :: n
    integer :: i
    character(len=2) :: backing_store
    valid = .true.
    if (len(goal)+1 .eq. n) return
    do i=1, size(blocks)
       if (index(blocks(i),goal(n:n)) .ne. 0) then
          backing_store = blocks(i)
          blocks(i) = ''
          solution(n) = i
          if (assign_block(goal, blocks, solution, n+1)) return
          blocks(i) = backing_store
       end if
    end do
    valid = .false.
    return
  end function assign_block

  subroutine ucase(a)
    implicit none
    character(len=*), intent(inout) :: a
    integer :: i, j
    do i = 1, len_trim(a)
       j = index('abcdefghijklmnopqrstuvwxyz',a(i:i))
       if (j .ne. 0) a(i:i) = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'(j:j)
    end do
  end subroutine ucase

end program abc

But if backtracking might be needed[edit]

The example set does not exercise the possible need for backtracking, as when an initial selection of blocks prevents completion because available letters have been used up. This can only arise when the same letter appears on more than one block and does so with different partners. The example set does contain duplicated letters, but they appear only via blocks with the same letters. Suppose instead that the block collection was AB, BC, CD, ... XY, YZ so that every letter appears twice except for A and Z. If the target word was STOPPED then both OP and PQ would be needed to supply P, but if the O had been supplied via OP then the second P would be unavailable. If instead the O were to be supplied by NO then all would be well.

The method involves the stack-style usage of array MOVE, but there is no explicit attempt at recursion. The array contains the possible moves at each level, and if necessary, a move made can later be retracted and an alternative sought. This is the standard style of playing board games such as chess via developing a "game tree", but in this case the tree traversal is not a large task.

The following source begins with some support routines. Subroutine PLAY inspects the collection of blocks to make various remarks, and function CANBLOCK reports on whether a word can be spelled out with the supplied blocks. The source requires only a few of the F90 features. The MODULE protocol eases communication, but the key feature is that subprograms can now declare arrays of a size determined on entry via parameters. Previously, a constant with the largest-possible size would be required.

      MODULE PLAYPEN	!Messes with a set of alphabet blocks.
       INTEGER MSG		!Output unit number.
       PARAMETER (MSG = 6)	!Standard output.
       INTEGER MS		!I dislike unidentified constants...
       PARAMETER (MS = 2)	!So this is the maximum number of lettered sides.
       INTEGER LETTER(26),SUPPLY(26)	!For counting the alphabet.
       CONTAINS
        SUBROUTINE SWAP(I,J)	!This really should be known to the compiler.
         INTEGER I,J,K		!Which could generate in-place code,
          K = I			!Using registers, maybe.
          I = J			!Or maybe, there are special op-codes.
          J = K			!Rather than this clunkiness.
        END SUBROUTINE SWAP	!And it should be for any type of thingy.

        INTEGER FUNCTION LSTNB(TEXT)  !Sigh. Last Not Blank.
Concocted yet again by R.N.McLean (whom God preserve) December MM.
Code checking reveals that the Compaq compiler generates a copy of the string and then finds the length of that when using the latter-day intrinsic LEN_TRIM. Madness!
Can't   DO WHILE (L.GT.0 .AND. TEXT(L:L).LE.' ')	!Control chars. regarded as spaces.
Curse the morons who think it good that the compiler MIGHT evaluate logical expressions fully.
Crude GO TO rather than a DO-loop, because compilers use a loop counter as well as updating the index variable.
Comparison runs of GNASH showed a saving of ~3% in its mass-data reading through the avoidance of DO in LSTNB alone.
Crappy code for character comparison of varying lengths is avoided by using ICHAR which is for single characters only.
Checking the indexing of CHARACTER variables for bounds evoked astounding stupidities, such as calculating the length of TEXT(L:L) by subtracting L from L!
Comparison runs of GNASH showed a saving of ~25-30% in its mass data scanning for this, involving all its two-dozen or so single-character comparisons, not just in LSTNB.
         CHARACTER*(*),INTENT(IN):: TEXT	!The bumf. If there must be copy-in, at least there need not be copy back.
         INTEGER L		!The length of the bumf.
          L = LEN(TEXT)		!So, what is it?
    1     IF (L.LE.0) GO TO 2	!Are we there yet?
          IF (ICHAR(TEXT(L:L)).GT.ICHAR(" ")) GO TO 2	!Control chars are regarded as spaces also.
          L = L - 1		!Step back one.
          GO TO 1		!And try again.
    2     LSTNB = L		!The last non-blank, possibly zero.
         RETURN			!Unsafe to use LSTNB as a variable.
        END FUNCTION LSTNB	!Compilers can bungle it.

        SUBROUTINE LETTERCOUNT(TEXT)	!Count the occurrences of A-Z.
         CHARACTER*(*) TEXT	!The text to inspect.
         INTEGER I,K		!Assistants.
          DO I = 1,LEN(TEXT)		!Step through the text.
            K = ICHAR(TEXT(I:I)) - ICHAR("A") + 1	!This presumes that A-Z have contiguous codes!
            IF (K.GE.1 .AND. K.LE.26) LETTER(K) = LETTER(K) + 1	!Not so with EBCDIC!!
          END DO			!On to the next letter.
        END SUBROUTINE LETTERCOUNT	!Be careful with LETTER.

        SUBROUTINE UPCASE(TEXT)	!In the absence of an intrinsic...
Converts any lower case letters in TEXT to upper case...
Concocted yet again by R.N.McLean (whom God preserve) December MM.
Converting from a DO loop evades having both an iteration counter to decrement and an index variable to adjust.
         CHARACTER*(*) TEXT	!The stuff to be modified.
c        CHARACTER*26 LOWER,UPPER	!Tables. a-z may not be contiguous codes.
c        PARAMETER (LOWER = "abcdefghijklmnopqrstuvwxyz")
c        PARAMETER (UPPER = "ABCDEFGHIJKLMNOPQRSTUVWXYZ")
CAREFUL!! The below relies on a-z and A-Z being contiguous, as is NOT the case with EBCDIC.
         INTEGER I,L,IT		!Fingers.
          L = LEN(TEXT)		!Get a local value, in case LEN engages in oddities.
          I = L			!Start at the end and work back..
    1     IF (I.LE.0) RETURN 	!Are we there yet? Comparison against zero should not require a subtraction.
c         IT = INDEX(LOWER,TEXT(I:I))	!Well?
c         IF (IT .GT. 0) TEXT(I:I) = UPPER(IT:IT)	!One to convert?
          IT = ICHAR(TEXT(I:I)) - ICHAR("a")		!More symbols precede "a" than "A".
          IF (IT.GE.0 .AND. IT.LE.25) TEXT(I:I) = CHAR(IT + ICHAR("A"))	!In a-z? Convert!
          I = I - 1			!Back one.
          GO TO 1			!Inspect..
        END SUBROUTINE UPCASE	!Easy.

        SUBROUTINE ORDERSIDE(LETTER)	!Puts the letters into order.
         CHARACTER*(*) LETTER	!The letters.
         INTEGER I,N,H		!Assistants.
         CHARACTER*1 T		!A scratchpad.
         LOGICAL CURSE		!A bit.
          N = LEN(LETTER)	!So, how many letters?
          H = N - 1		!Last - First, and not +1.
          IF (H.LE.0) RETURN	!Ha ha.
    1     H = MAX(1,H*10/13)		!The special feature.
          IF (H.EQ.9 .OR. H.EQ.10) H = 11	!A twiddle.
          CURSE = .FALSE.		!So far, so good.
          DO I = N - H,1,-1		!If H = 1, this is a BubbleSort.
            IF (LETTER(I:I).LT.LETTER(I + H:I + H)) THEN	!One compare.
              T = LETTER(I:I)			!One swap.
              LETTER(I:I) = LETTER(I + H:I + H)	!Alas, no SWAP(A,B)
              LETTER(I + H:I + H) = T		!Is recognised by the compiler.
              CURSE = .TRUE.		!If once a tiger is seen...
            END IF			!So much for that comparison.
          END DO			!On to the next.
          IF (CURSE .OR. H.GT.1) GO TO 1!Another pass?
        END SUBROUTINE ORDERSIDE	!Simple enough.
        SUBROUTINE ORDERBLOCKS(N,SOME)	!Puts the collection of blocks into order.
         INTEGER N		!The number of blocks.
         CHARACTER*(*) SOME(:)	!Their lists of letters.
         INTEGER I,H		!Assistants.
         CHARACTER*(LEN(SOME(1))) T	!A scratchpad matching an element of SOME.
         LOGICAL CURSE			!Since there is still no SWAP(SOME(I),SOME(I + H)).
          H = N - 1		!So here comes another CombSort.
          IF (H.LE.0) RETURN	!With standard suspicion.
    1     H = MAX(1,H*10/13)		!This is the outer loop.
          IF (H.EQ.9 .OR. H.EQ.10) H = 11	!This is a fiddle.
          CURSE = .FALSE.		!Start the next pass in hope.
          DO I = N - H,1,-1		!Going backwards, just for fun.
            IF (SOME(I).LT.SOME(I + H)) THEN	!So then?
              T = SOME(I)		!Disorder.
              SOME(I) = SOME(I + H)	!So once again,
              SOME(I + H) = T		!Swap the two miscreants.
              CURSE = .TRUE.		!And remember.
            END IF			!So much for that comparison.
          END DO			!On to the next.
          IF (CURSE .OR. H.GT.1) GO TO 1!Are we there yet?
        END SUBROUTINE ORDERBLOCKS	!Not much code, but ringing the changes is still tedious.

        SUBROUTINE PLAY(N,SOME)	!Mess about with the collection of blocks.
         INTEGER N		!Their number.
         CHARACTER*(*) SOME(:)	!Their letters.
         INTEGER NH,HIT(N)	!A list of blocks.
         INTEGER B,I,J,K,L,M	!Assistants.
         CHARACTER*1 C		!A letter of the moment.
          L = LEN(SOME(1))	!The maximum number of letters to any block.
Cast the collection on to the floor.
          WRITE (MSG,1) N,L,SOME	!Announce the set as it is supplied.
    1     FORMAT (I7," blocks, with at most",I2," letters:",66(1X,A))
Change the "orientation" of some blocks.
          DO B = 1,N		!Step through each block.
            CALL UPCASE(SOME(B))	!Paranoia rules.
            CALL ORDERSIDE(SOME(B))	!Put its letter list into order.
          END DO		!On to the next block.
          WRITE (MSG,2) SOME	!Reveal the orderly array.
    2     FORMAT (6X,"... the letters in reverse order:",66(1X,A))
Collate the collection of blocks.
          CALL ORDERBLOCKS(N,SOME)	!Now order the blocks by their letters.
          WRITE (MSG,3) SOME		!Reveal them in neato order.
    3     FORMAT (7X,"... the blocks in reverse order:",66(1X,A))
Count the appearances of the letters of the alphabet.
          LETTER = 0		!Enough of shuffling blocks around.
          DO B = 1,N		!Now inspect their collective letters.
            CALL LETTERCOUNT(SOME(B))	!A block's worth at a go.
          END DO		!On to the next block.
          SUPPLY = LETTER	!Save the counts of supplied letters.
          WRITE (MSG,4) (CHAR(ICHAR("A") + I - 1),I = 1,26),SUPPLY	!Results.
    4     FORMAT (15X,"Letters of the alphabet:",26A<MS + 1>,/,	!First, a line with A ... Z.
     1     11X,"... number thereof supplied:",26I<MS + 1>)	!Then a line of the associated counts.
Check for blocks with duplicated letters.
          WRITE (MSG,5)		!Announce.
    5     FORMAT (8X,"Blocks with duplicated letters:",$)	!Further output impends.
          M = 0			!No duplication found.
          DO B = 1,N		!So step through each block.
         JJ:DO J = 2,L			!Inspecting successive letters of the block,
              IF (SOME(B)(J:J).LE." ") EXIT JJ	!Provided they've not run out.
              DO K = 1,J - 1			!To see if it has appeared earlier.
                IF (SOME(B)(K:K).LE." ") EXIT JJ!Reverse order means that spaces will be at the end!
                IF (SOME(B)(J:J).EQ.SOME(B)(K:K)) THEN	!Well?
                  M = M + 1		!A match!
                  WRITE (MSG,6) SOME(B)	!Name the block.
    6             FORMAT (1X,A,$)	!With further output still impending,
                  EXIT JJ		!And give up on this block.
                END IF			!One duplicated letter is sufficient for its downfall.
              END DO			!Next letter up.
            END DO JJ			!On to the next letter of the block.
          END DO		!On to the next block.
          CALL HIC(M)		!Show the count and end the line.
Check for duplicate blocks, knowing that the array of blocks is ordered.
          WRITE (MSG,7)		!Announce.
    7     FORMAT (21X,"Duplicated blocks:",$)	!Again, leave the line dangling.
          K = 0			!No duplication found.
          B = 1			!Syncopation.
   70     B = B + 1		!Advance one.
          IF (B.GT.N) GO TO 72	!Are we there yet?
          IF (SOME(B).NE.SOME(B - 1)) GO TO 70	!No match? Search on.
          K = K + 1		!A match is counted.
          WRITE (MSG,6) SOME(B)	!Name it.
   71     B = B + 1		!And speed through continued matching.
          IF (B.GT.N) GO TO 72	!Unless we're of the end.
          IF (SOME(B).EQ.SOME(B - 1)) GO TO 71	!Continued matching?
          GO TO 70		!Mismatch: resume the normal scan.
   72     CALL HIC(K)		!So much for that.
Check for duplicated letters across different blocks.
          IF (ALL(SUPPLY.LE.1)) RETURN	!Unless there are no duplicated letters.
          WRITE (MSG,8)		!Announce.
    8     FORMAT ("Duplicated letters on different blocks:",$)	!More to come.
          K = 0		!Start another count.
          DO I = 1,26		!A well-known span.
            IF (SUPPLY(I).LE.1) CYCLE	!Any duplicated letters?
            C = CHAR(ICHAR("A") + I - 1)!Yes. This is the character.
            NH = 0		!So, how many blocks contribute?
            DO B = 1,N		!Find out.
              IF (INDEX(SOME(B),C).GT.0) THEN	!On this block?
                NH = NH + 1		!Yes.
                HIT(NH) = B		!Keep track of which.
              END IF			!So much for that block.
            END DO		!On to the next.
            IF (ANY(SOME(HIT(2:NH)) .NE. SOME(HIT(1)))) THEN	!All have the same collection of letters?
              K = K + 1			!No!
              WRITE (MSG,9) C		!Name the heterogenously supported letter.
    9         FORMAT (A<MS + 1>,$)	!Use the same spacing even though one character only.
            END IF		!So much for that letter's search.
          END DO		!On to the next letter.
          CALL HIC(K)	!Finish the line with the count report.
         CONTAINS	!This is used often enough.
          SUBROUTINE HIC(N)	!But has very specific context.
           INTEGER N			!The count.
            IF (N.LE.0) WRITE (MSG,*) "None."	!Yes, we have no bananas.
            IF (N.GT.0) WRITE (MSG,*) N		!Either way, end the line.
          END SUBROUTINE HIC	!This service routine is not needed elsewhere.
        END SUBROUTINE PLAY	!Look mummy! All the blockses are neatened!

        LOGICAL FUNCTION CANBLOCK(WORD,N,SOME)	!Can the blocks spell out the word?
Creates a move tree based on the letters of WORD and for each, the blocks available.
         CHARACTER*(*) WORD	!The word to spell out.
         INTEGER N		!The number of blocks.
         CHARACTER*(*) SOME(:)	!The blocks and their letters.
         INTEGER NA,AVAIL(N)	!Say not the struggle naught availeth!
         INTEGER NMOVE(LEN(WORD))	!I need a list of acceptable blocks,
         INTEGER MOVE(LEN(WORD),N)	!One list for each letter of WORD.
         INTEGER I,L,S		!Assistants.
         CHARACTER*1 C		!The letter of the moment.
          CANBLOCK = .FALSE.		!Initial pessimism.
          L = LSTNB(WORD)		!Ignore trailing spaces.
          IF (L.GT.N) RETURN		!Enough blocks?
          LETTER = 0				!To make rabbit stew,
          CALL LETTERCOUNT(WORD(1:L))		!First catch your rabbit.
          IF (ANY(SUPPLY .LT. LETTER)) RETURN	!The larder is lacking.
          NA = N			!Prepare a list.
          FORALL (I = 1:N) AVAIL(I) = I	!That fingers every block.
          I = 0		!Step through the letters of the WORD.
Chug through the letters of the WORD.
    1     I = I + 1	!One letter after the other.
          IF (I.GT.L) GO TO 100	!Yay! We're through!
          C = WORD(I:I)		!The letter of the moment.
          NMOVE(I) = 0		!No moves known at this new level.
          DO S = 1,NA		!So, look for them amongst the available slots.
            IF (INDEX(SOME(AVAIL(S)),C) .GT. 0) THEN	!A hit?
              NMOVE(I) = NMOVE(I) + 1	!Yes! Count up another possible move.
              MOVE(I,NMOVE(I)) = S	!Remember its slot.
            END IF			!So much for that block.
          END DO		!On to the next.
    2     IF (NMOVE(I).GT.0) THEN	!Have we any moves?
            S = MOVE(I,NMOVE(I))	!Yes! Recover the last found.
            NMOVE(I) = NMOVE(I) - 1	!Uncount, as it is about to be used.
            IF (S.NE.NA) CALL SWAP(AVAIL(S),AVAIL(NA))	!This block is no longer available.
            NA = NA - 1			!Shift the boundary back.
            GO TO 1			!Try the next letter!
          END IF		!But if we can't find a move at that level...
          I = I - 1		!Retreat a level.
          IF (I.LE.0) RETURN	!Oh dear!
          S = MOVE(I,NMOVE(I) + 1)	!Undo the move that had been made at this level.
          NA = NA + 1			!And make its block is re-available.
          IF (S.NE.NA) CALL SWAP(AVAIL(S),AVAIL(NA))	!Move it back.
          GO TO 2		!See what moves remain at this level.
Completed!
  100     CANBLOCK = .TRUE.	!That's a relief.
        END FUNCTION CANBLOCK	!Some revisions might have been made.
      END MODULE PLAYPEN	!No sand here.

      USE PLAYPEN	!Just so.
      INTEGER HAVE,TESTS		!Parameters for the specified problem.
      PARAMETER (HAVE = 20, TESTS = 7)	!Number of blocks, number of tests.
      CHARACTER*(MS) BLOCKS(HAVE)	!Have blocks, will juggle.
      DATA BLOCKS/"BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",	!The specified set
     1            "JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"/	!Of letter blocks.
      CHARACTER*8 WORD(TESTS)		!Now for the specified test words.
      LOGICAL ANS(TESTS),T,F		!And the given results.
      PARAMETER (T = .TRUE., F = .FALSE.)	!Enable a more compact specification.
      DATA WORD/"A","BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE"/	!So that these
      DATA  ANS/ T ,    T ,    F ,     T ,      F ,     T ,       T /	!Can be aligned.
      LOGICAL YAY
      INTEGER I

      WRITE (MSG,1)
    1 FORMAT ("Arranges alphabet blocks, attending only to the ",
     1 "letters on the blocks, and ignoring case and orientation.",/)

      CALL PLAY(HAVE,BLOCKS)	!Some fun first.

      WRITE (MSG,'(/"Now to see if some words can be spelled out.")')
      DO I = 1,TESTS
        CALL UPCASE(WORD(I))
        YAY = CANBLOCK(WORD(I),HAVE,BLOCKS)
        WRITE (MSG,*) YAY,ANS(I),YAY.EQ.ANS(I),WORD(I)
      END DO
      END

Output: the first column of T/F is the report from CANBLOCK, the second is the expected answer from the example, and the third is whether the two are in agreement.

Arranges alphabet blocks, attending only to the letters on the blocks, and ignoring case and orientation.

     20 blocks, with at most 2 letters: BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
      ... the letters in reverse order: OB XK QD PC NA TG RE TG QD SF WJ UH VI NA OB RE SF YL PC ZM
       ... the blocks in reverse order: ZM YL XK WJ VI UH TG TG SF SF RE RE QD QD PC PC OB OB NA NA
               Letters of the alphabet:  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z
           ... number thereof supplied:  2  2  2  2  2  2  2  1  1  1  1  1  1  2  2  2  2  2  2  2  1  1  1  1  1  1
        Blocks with duplicated letters: None.
                     Duplicated blocks: TG SF RE QD PC OB NA           7
Duplicated letters on different blocks: None.

Now to see if some words can be spelled out.
 T T T A
 T T T BARK
 F F T BOOK
 T T T TREAT
 F F T COMMON
 T T T SQUAD
 T T T CONFUSE

FreeBASIC[edit]

' version 28-01-2019
' compile with: fbc -s console

Dim As String blocks(1 To 20, 1 To 2) => {{"B", "O"}, {"X", "K"}, {"D", "Q"}, _
{"C", "P"}, {"N", "A"}, {"G", "T"}, {"R", "E"}, {"T", "G"}, {"Q", "D"}, _
{"F", "S"}, {"J", "W"}, {"H", "U"}, {"V", "I"}, {"A", "N"}, {"O", "B"}, _
{"E", "R"}, {"F", "S"}, {"L", "Y"}, {"P", "C"}, {"Z", "M"}}

Dim As UInteger i, x, y, b()
Dim As String word, char
Dim As boolean possible

Do
    Read word
    If word = "" Then Exit Do
    word = UCase(word)
    ReDim b(1 To 20)
    possible = TRUE

    For i = 1 To Len(word)
        char = Mid(word, i, 1)

        For x = 1 To 20
            If b(x) = 0 Then
                If blocks(x, 1) = char Or blocks(x, 2) = char Then
                    b(x) = 1
                    Exit For
                End If
            End If
        Next
        If x = 21 Then possible = FALSE
    Next

    Print word, possible
Loop

Data  "A", "Bark", "Book", "Treat", "Common", "Squad", "Confuse", ""

' empty keyboard buffer
While InKey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End
Output:
A           true
BARK          true
BOOK          false
TREAT         true
COMMON        false
SQUAD         true
CONFUSE       true


FutureBasic[edit]

include "NSLog.incl"

local fn CanBlocksSpell( w as CFStringRef ) as CFStringRef
  NSUInteger        i, j
  CFStringRef       cFinal = @"", result = @"NO"
  CFMutableArrayRef blocks
  
  blocks = fn MutableArrayWithArray( @[@"BO", @"XK", @"DQ", @"CP",¬
  @"NA", @"GT", @"RE", @"TG", @"QD", @"FS", @"JW", @"HU", @"VI",¬
  @"AN", @"OB",   @"ER", @"FS", @"LY", @"PC", @"ZM"] )
  
  CFStringRef cfStr = fn StringUppercaseString( w )
  NSUInteger length = fn StringLength( cfStr )
  NSUInteger count  = fn ArrayCount( blocks )
  
  for i = 0 to length - 1
    for j = 0 to count - 1
      CFStringRef charStr    = mid( cfStr, i, 1 )
      CFStringRef compareStr = fn ArrayObjectAtIndex( blocks, j )
      CFStringRef testStr1   = mid( compareStr, 0, 1 )
      CFStringRef testStr2   = mid( compareStr, 1, 1 )
      if ( fn StringIsEqual( charStr, testStr1 ) == YES )
        cFinal = fn StringByAppendingString( cFinal, testStr1 ) : MutableArrayReplaceObjectAtIndex( blocks, @"  ", j ) : exit for
      end if
      if ( fn StringIsEqual( charStr, testStr2 ) == YES )
        cFinal = fn StringByAppendingString( cFinal, testStr2 ) : MutableArrayReplaceObjectAtIndex( blocks, @"  ", j ) : exit for
      end if
    next
  next
  if fn StringIsEqual( cFinal, cfStr ) == YES then result = @"YES"
end fn = result

NSLog( @"a:       Can blocks spell? %@", fn CanBlocksSpell( @"a"       ) )
NSLog( @"Bark:    Can blocks spell? %@", fn CanBlocksSpell( @"Bark"    ) )
NSLog( @"BOOK:    Can blocks spell? %@", fn CanBlocksSpell( @"BOOK"    ) )
NSLog( @"TrEaT:   Can blocks spell? %@", fn CanBlocksSpell( @"TrEaT"   ) )
NSLog( @"COMMON:  Can blocks spell? %@", fn CanBlocksSpell( @"COMMON"  ) )
NSLog( @"Squad:   Can blocks spell? %@", fn CanBlocksSpell( @"Squad"   ) )
NSLog( @"conFUse: Can blocks spell? %@", fn CanBlocksSpell( @"conFUse" ) )

HandleEvents
Output:
a:       Can blocks spell? YES
Bark:    Can blocks spell? YES
BOOK:    Can blocks spell? NO
TrEaT:   Can blocks spell? YES
COMMON:  Can blocks spell? NO
Squad:   Can blocks spell? YES
conFUse: Can blocks spell? YES

Gambas[edit]

Click this link to run this code

Public Sub Main()
Dim sCheck As String[] = ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"]
Dim sBlock As String[] = ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"]
Dim sList As New String[]
Dim siCount, siLoop As Short
Dim sTemp, sAnswer As String

For Each sTemp In sCheck
  sAnswer = ""
  sList = sBlock.Copy()
  For siCount = 1 To Len(sTemp)
    For siLoop = 0 To sList.Max
      If InStr(sList[siLoop], Mid(sTemp, siCount, 1)) Then
        sList.Extract(siLoop, 1)
        sAnswer &= Mid(sTemp, siCount, 1)
        Break
      Endif
    Next
  Next

 If sAnswer = sTemp Then 
   Print sTemp & " - True"
 Else
   Print sTemp & " - False"
 End If
Next

End

Output:

A - True
BARK - True
BOOK - False
TREAT - True
COMMON - False
SQUAD - True
CONFUSE - True

Go[edit]

package main

import (
	"fmt"
	"strings"
)

func newSpeller(blocks string) func(string) bool {
	bl := strings.Fields(blocks)
	return func(word string) bool {
		return r(word, bl)
	}
}

func r(word string, bl []string) bool {
	if word == "" {
		return true
	}
	c := word[0] | 32
	for i, b := range bl {
		if c == b[0]|32 || c == b[1]|32 {
			bl[i], bl[0] = bl[0], b
			if r(word[1:], bl[1:]) == true {
				return true
			}
			bl[i], bl[0] = bl[0], bl[i]
		}
	}
	return false
}

func main() {
	sp := newSpeller(
		"BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM")
	for _, word := range []string{
		"A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"} {
		fmt.Println(word, sp(word))
	}
}
Output:
A true
BARK true
BOOK false
TREAT true
COMMON false
SQUAD true
CONFUSE true

Groovy[edit]

Solution:

class ABCSolver {
    def blocks

    ABCSolver(blocks = []) { this.blocks = blocks }

    boolean canMakeWord(rawWord) {
        if (rawWord == '' || rawWord == null) { return true; }
        def word = rawWord.toUpperCase()
        def blocksLeft = [] + blocks
        word.every { letter -> blocksLeft.remove(blocksLeft.find { block -> block.contains(letter) }) }
    }
}

Test:

def a = new ABCSolver(["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
                      "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"])

['', 'A', 'BARK', 'book', 'treat', 'COMMON', 'SQuAd', 'CONFUSE'].each {
    println "'${it}': ${a.canMakeWord(it)}"
}
Output:
'': true
'A': true
'BARK': true
'book': false
'treat': true
'COMMON': false
'SQuAd': true
'CONFUSE': true

Harbour[edit]

Harbour Project implements a cross-platform Clipper/xBase compiler.

PROCEDURE Main()

   LOCAL cStr

   FOR EACH cStr IN { "A", "BARK", "BooK", "TrEaT", "comMON", "sQuAd", "Confuse" }
      ? PadL( cStr, 10 ), iif( Blockable( cStr ), "can", "cannot" ), "be spelled with blocks."
   NEXT

   RETURN

STATIC FUNCTION Blockable( cStr )

   LOCAL blocks := { ;
      "BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", ;
      "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM" }

   LOCAL cFinal := ""
   LOCAL i, j

   cStr := Upper( cStr )

   FOR i := 1 TO Len( cStr )
      FOR EACH j IN blocks
         IF SubStr( cStr, i, 1 ) $ j
            cFinal += SubStr( cStr, i, 1 )
            j := ""
            EXIT
         ENDIF
      NEXT
   NEXT

   RETURN cFinal == cStr
Output:
         A can be spelled with blocks.
      BARK can be spelled with blocks.
      BooK cannot be spelled with blocks.
     TrEaT can be spelled with blocks.
    comMON cannot be spelled with blocks.
     sQuAd can be spelled with blocks.
   Confuse can be spelled with blocks.

Haskell[edit]

The following function returns a list of all the solutions. Since Haskell is lazy, testing whether the list is null will only do the minimal amount of work necessary to determine whether a solution exists.

import Data.List (delete)
import Data.Char (toUpper)

-- returns list of all solutions, each solution being a list of blocks
abc :: (Eq a) => [[a]] -> [a] -> [[[a]]]
abc _ [] = [[]]
abc blocks (c:cs) = [b:ans | b <- blocks, c `elem` b,
                             ans <- abc (delete b blocks) cs]

blocks = ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
          "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"]

main :: IO ()
main = mapM_ (\w -> print (w, not . null $ abc blocks (map toUpper w)))
         ["", "A", "BARK", "BoOK", "TrEAT", "COmMoN", "SQUAD", "conFUsE"]
Output:
("",True)
("A",True)
("BARK",True)
("BoOK",False)
("TrEAT",True)
("COmMoN",False)
("SQUAD",True)
("conFUsE",True)

Or, in terms of the bind operator:

import Data.Char (toUpper)
import Data.List (delete)


----------------------- ABC PROBLEM ----------------------

spellWith :: [String] -> String -> [[String]]
spellWith _ [] = [[]]
spellWith blocks (x : xs) = blocks >>= go
  where
    go b
      | x `elem` b = (b :) <$> spellWith (delete b blocks) xs
      | otherwise = []


--------------------------- TEST -------------------------
main :: IO ()
main =
  mapM_
    ( print
        . ((,) <*>)
          (not . null . spellWith blocks . fmap toUpper)
    )
    [ "",
      "A",
      "BARK",
      "BoOK",
      "TrEAT",
      "COmMoN",
      "SQUAD",
      "conFUsE"
    ]

blocks :: [String]
blocks =
  words $
    "BO XK DQ CP NA GT RE TG QD FS JW"
      <> " HU VI AN OB ER FS LY PC ZM"
Output:
("",True)
("A",True)
("BARK",True)
("BoOK",False)
("TrEAT",True)
("COmMoN",False)
("SQUAD",True)
("conFUsE",True)

Icon and Unicon[edit]

Translation of: C

Works in both languages:

procedure main(A)
    blocks := ["bo","xk","dq","cp","na","gt","re","tg","qd","fs",
               "jw","hu","vi","an","ob","er","fs","ly","pc","zm",&null]
    every write("\"",word := !A,"\" ",checkSpell(map(word),blocks)," with blocks.")
end

procedure checkSpell(w,blocks)
    blks := copy(blocks)
    w ? return if canMakeWord(blks) then "can be spelled"
                                    else "can not be spelled"
end

procedure canMakeWord(blks)
    c := move(1) | return
    if /blks[1] then fail
    every i := 1 to *blks do {
        if /blks[i] then (move(-1),fail)
        if c == !blks[i] then {  
            blks[1] :=: blks[i]
            if canMakeWord(blks[2:0]) then return
            blks[1] :=: blks[i]
            }
        }
end

Sample run:

->abc "" A BARK BOOK TREAT COMMON SQUAD CONFUSE
"" can be spelled with blocks.
"A" can be spelled with blocks.
"BARK" can be spelled with blocks.
"BOOK" can not be spelled with blocks.
"TREAT" can be spelled with blocks.
"COMMON" can not be spelled with blocks.
"SQUAD" can be spelled with blocks.
"CONFUSE" can be spelled with blocks.
->

J[edit]

Solution:

reduce=: verb define
  'rows cols'=. i.&.> $y
  for_c. cols do.
    r=. 1 i.~ c {"1 y             NB. row idx of first 1 in col
    if. r = #rows do. continue. end.
    y=. 0 (<((r+1)}.rows);c) } y  NB. zero rest of col
    y=. 0 (<(r;(c+1)}.cols)) } y  NB. zero rest of row
  end.
)

abc=: *./@(+./)@reduce@(e."1~ ,)&toupper :: 0:

Examples:

   Blocks=:  ];._2 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM '
   ExampleWords=: <;._2 'A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE '

   Blocks&abc &> ExampleWords
1 1 0 1 0 1 1
   require 'format/printf'
   '%10s  %s' printf (dquote ; 'FT' {~ Blocks&abc) &> ExampleWords
       "A"  T
    "BaRK"  T
    "BOoK"  F
   "tREaT"  T
  "COmMOn"  F
   "SqUAD"  T
 "CoNfuSE"  T

Tacit version

delElem=: {~<@<@<
uppc=:(-32*96&<*.123&>)&.(3&u:) 
reduc=: ] delElem  1 i.~e."0 1
forms=:  (1 - '' -: (reduc L:0/ :: (a:"_)@(<"0@],<@[))&uppc) L:0
Output:
   (,.Blocks&forms) ExampleWords
┌───────┬─┐
│A      │1│
├───────┼─┤
│BaRK   │1│
├───────┼─┤
│BOoK   │0│
├───────┼─┤
│tREaT  │1│
├───────┼─┤
│COmMOn │0│
├───────┼─┤
│SqUAD  │1│
├───────┼─┤
│CoNfuSE│1│
└───────┴─┘

Alternative Implementation[edit]

Another approach might be:

Blocks=:  >;:'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM '
ExampleWords=: ;: 'A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE '

canform=:4 :0
  word=: toupper y
  need=: #/.~ word,word
  relevant=: (x +./@e."1 word) # x
  candidates=: word,"1>,{{relevant
  +./(((#need){. #/.~)"1 candidates) */ .>:need
)

Example use:

   Blocks canform 0{::ExampleWords
1
   Blocks canform 1{::ExampleWords
1
   Blocks canform 2{::ExampleWords
0
   Blocks canform 3{::ExampleWords
1
   Blocks canform 4{::ExampleWords
0
   Blocks canform 5{::ExampleWords
1
   Blocks canform 6{::ExampleWords
1

Explanation:

We only need to consider blocks which contain letters in common with a normalized (upper case) version of the desired word. But we do need to consider all possible combinations of letters from those blocks (see talk page discussion of words like 'ABBA' for more on this issue).

We can classify possibilities by counting how many of each letter occur. If a candidate has at least as many of the required letters as a test case constructed from the word itself, it's a valid candidate.

For example:

   Blocks canform 0{::ExampleWords
1
   word
A
   need
2
   relevant
NA
AN
   candidates
ANA
ANN
AAA
AAN

Here, the word is simply 'A', and we have two blocks to consider for our word: AN and NA. So we form all possible combinations of the letters of those two bocks, prefix each of them with our word and test whether any of them contain two copies of the letters of our word. (As it happens, three of the candidates are valid, for this trivial example.)

Java[edit]

Translation of: C
Works with: Java version 1.6+
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class ABC {

    public static void main(String[] args) {
        List<String> blocks = Arrays.asList(
                "BO", "XK", "DQ", "CP", "NA",
                "GT", "RE", "TG", "QD", "FS",
                "JW", "HU", "VI", "AN", "OB",
                "ER", "FS", "LY", "PC", "ZM");

        for (String word : Arrays.asList("", "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE")) {
            System.out.printf("%s: %s%n", word.isEmpty() ? "\"\"" : word, canMakeWord(word, blocks));
        }
    }

    public static boolean canMakeWord(String word, List<String> blocks) {
        if (word.isEmpty())
            return true;

        char c = word.charAt(0);
        for (int i = 0; i < blocks.size(); i++) {
            String b = blocks.get(i);
            if (b.charAt(0) != c && b.charAt(1) != c)
                continue;
            Collections.swap(blocks, 0, i);
            if (canMakeWord(word.substring(1), blocks.subList(1, blocks.size())))
                return true;
            Collections.swap(blocks, 0, i);
        }

        return false;
    }
}
Output:
"": true
A: true
BARK: true
book: false
treat: true
COMMON: false
SQuAd: true
CONFUSE: true

JavaScript[edit]

ES5[edit]

Imperative[edit]

The following method uses regular expressions and the string replace function to allow more support for older browsers.

var blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";

function CheckWord(blocks, word) {
   // Makes sure that word only contains letters.
   if(word !== /([a-z]*)/i.exec(word)[1]) return false;
   // Loops through each character to see if a block exists.
   for(var i = 0; i < word.length; ++i)
   {
      // Gets the ith character.
      var letter = word.charAt(i);
      // Stores the length of the blocks to determine if a block was removed.
      var length = blocks.length;
      // The regexp gets constructed by eval to allow more browsers to use the function.
      var reg = eval("/([a-z]"+letter+"|"+letter+"[a-z])/i");
      // This does the same as above, but some browsers do not support...
      //var reg = new RegExp("([a-z]"+letter+"|"+letter+"[a-z])", "i");
      // Removes all occurrences of the match. 
      blocks = blocks.replace(reg, "");
      // If the length did not change then a block did not exist.
      if(blocks.length === length) return false;
   }
   // If every character has passed then return true.
   return true;
};

var words = [
   "A",
   "BARK", 
   "BOOK", 
   "TREAT", 
   "COMMON", 
   "SQUAD", 
   "CONFUSE" 
];

for(var i = 0;i<words.length;++i)
   console.log(words[i] + ": " + CheckWord(blocks, words[i]));

Result:

A: true
BARK: true
BOOK: false
TREAT: true
COMMON: false
SQUAD: true
CONFUSE: true

Functional[edit]

(function (strWords) {

    var strBlocks =
        'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM',
        blocks = strBlocks.split(' ');

    function abc(lstBlocks, strWord) {
        var lngChars = strWord.length;

        if (!lngChars) return [];

        var b = lstBlocks[0],
            c = strWord[0];

        return chain(lstBlocks, function (b) {
            return (b.indexOf(c.toUpperCase()) !== -1) ? [
                (b + ' ').concat(
                    abc(removed(b, lstBlocks), strWord.slice(1)))
            ] : [];
        })
    }

    // Monadic bind (chain) for lists
    function chain(xs, f) {
        return [].concat.apply([], xs.map(f));
    }

    // a -> [a] -> [a]
    function removed(x, xs) {
        var h = xs.length ? xs[0] : null,
            t = h ? xs.slice(1) : [];

        return h ? (
            h === x ? t : [h].concat(removed(x, t))
        ) : [];
    }

    function solution(strWord) {
        var strAttempt = abc(blocks, strWord)[0].split(',')[0];

        // two chars per block plus one space -> 3
        return strWord + ((strAttempt.length === strWord.length * 3) ?
            ' -> ' + strAttempt : ': [no solution]');
    }

    return strWords.split(' ').map(solution).join('\n');

})('A bark BooK TReAT COMMON squAD conFUSE');
Output:
A -> NA 
bark -> BO NA RE XK 
BooK: [no solution]
TReAT -> GT RE ER NA TG 
COMMON: [no solution]
squAD -> FS DQ HU NA QD 
conFUSE -> CP BO NA FS HU FS RE

ES6[edit]

Imperative[edit]

let characters = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";
let blocks = characters.split(" ").map(pair => pair.split(""));
 
function isWordPossible(word) {
  var letters = [...word.toUpperCase()];
  var length = letters.length;
  var copy = new Set(blocks);

  for (let letter of letters) {
    for (let block of copy) {
      let index = block.indexOf(letter);
 
      if (index !== -1) {
        length--;
        copy.delete(block);
        break;  
      }
    }

  }
  return !length;
}    
 
[ 
  "A", 
  "BARK", 
  "BOOK", 
  "TREAT", 
  "COMMON", 
  "SQUAD", 
  "CONFUSE" 
].forEach(word => console.log(`${word}: ${isWordPossible(word)}`));

Result:

A: true
BARK: true
BOOK: false
TREAT: true
COMMON: false
SQUAD: true
CONFUSE: true


Functional[edit]

Translation of: Haskell
(() => {
    "use strict";

    // ------------------- ABC BLOCKS --------------------

    // spellWith :: [(Char, Char)] -> [Char] -> [[(Char, Char)]]
    const spellWith = blocks =>
        wordChars => !Boolean(wordChars.length) ? [
            []
        ] : (() => {
            const [x, ...xs] = wordChars;

            return blocks.flatMap(
                b => b.includes(x) ? (
                    spellWith(
                        deleteBy(
                            p => q => (p[0] === q[0]) && (
                                p[1] === q[1]
                            )
                        )(b)(blocks)
                    )(xs)
                    .flatMap(bs => [b, ...bs])
                ) : []
            );
        })();


    // ---------------------- TEST -----------------------
    const main = () => {
        const blocks = (
            "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
        ).split(" ");

        return [
                "", "A", "BARK", "BoOK", "TrEAT",
                "COmMoN", "SQUAD", "conFUsE"
            ]
            .map(
                x => JSON.stringify([
                    x, !Boolean(
                        spellWith(blocks)(
                            [...x.toLocaleUpperCase()]
                        )
                        .length
                    )
                ])
            )
            .join("\n");
    };

    // ---------------- GENERIC FUNCTIONS ----------------

    // deleteBy :: (a -> a -> Bool) -> a -> [a] -> [a]
    const deleteBy = fEq =>
        x => {
            const go = xs => Boolean(xs.length) ? (
                fEq(x)(xs[0]) ? (
                    xs.slice(1)
                ) : [xs[0], ...go(xs.slice(1))]
            ) : [];

            return go;
        };

    // MAIN ---
    return main();
})();
Output:
["",true]
["A",true]
["BARK",true]
["BoOK",false]
["TrEAT",true]
["COmMoN",false]
["SQUAD",true]
["conFUsE",true]

jq[edit]

The problem description seems to imply that if a letter, X, appears on more than one block, its partner will be the same on all blocks. This makes the problem trivial.
# when_index(cond;ary) returns the index of the first element in ary
# that satisfies cond; it uses a helper function that takes advantage
# of tail-recursion optimization in recent versions of jq.
def index_when(cond; ary):
  # state variable: counter
  def when: if . >= (ary | length) then null
            elif ary[.] | cond then . 
            else (.+1) | when
            end;
  0 | when;

# Attempt to match a single letter with a block;
# return null if no match, else the remaining blocks
def match_letter(letter):
  . as $ary | index_when( index(letter); $ary ) as $ix
  | if $ix == null then null
    else del( .[$ix] )
    end;

# Usage: string | abc(blocks)
def abc(blocks):
  if length == 0 then true
  else
    .[0:1] as $letter
    | (blocks | match_letter( $letter )) as $blks
    | if $blks == null then false
      else .[1:] | abc($blks)
      end
  end;
Task:
def task:
  ["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
   "JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"] as $blocks
  | ("A", "BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE")
  | "\(.) : \( .|abc($blocks) )" ;task
Output:
A : true
BARK : true
BOOK : false
TREAT : true
COMMON : false
SQUAD : true
CONFUSE : true

Jsish[edit]

Based on Javascript ES5 imperative solution.

#!/usr/bin/env jsish
/* ABC problem, in Jsish.  Can word be spelled with the given letter blocks. */
var blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";
 
function CheckWord(blocks, word) {
   var re = /([a-z]*)/i;
   if (word !== re.exec(word)[0]) return false;
   for (var i = 0; i < word.length; i++) {
      var letter = word.charAt(i);
      var length = blocks.length;
      // trying both sides
      var reg = new RegExp("([a-z]"+letter + "|" + letter+"[a-z])", "i");
      // remove block once a letter is used
      blocks = blocks.replace(reg, "");
      if (blocks.length === length) return false;
   }
   return true;
};

var words = [ "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE" ];

puts("Using blocks:", blocks);
for(var i = 0; i<words.length; i++)
    puts(CheckWord(blocks, words[i]) ? "can" : "can't", "spell", words[i]);

/*
=!EXPECTSTART!=
Using blocks: BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
can spell A
can spell BARK
can't spell BOOK
can spell TREAT
can't spell COMMON
can spell SQUAD
can spell CONFUSE
=!EXPECTEND!=
*/
Output:
prompt$ jsish ABCProblem.jsi
Using blocks: BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
can spell A
can spell BARK
can't spell BOOK
can spell TREAT
can't spell COMMON
can spell SQUAD
can spell CONFUSE

prompt$ jsish -u ABCProblem.jsi
[PASS] ABCProblem.jsi

Julia[edit]

using Printf

function abc(str::AbstractString, list)
    isempty(str) && return true
    for i in eachindex(list)
        str[end] in list[i] &&
            any([abc(str[1:end-1], deleteat!(copy(list), i))]) &&
            return true
    end
    return false
end

let test = ["A", "BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE"],
    list = ["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
            "JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"]
    for str in test
        @printf("%-8s |  %s\n", str, abc(str, list))
    end
end
Output:
A        |  true
BARK     |  true
BOOK     |  false
TREAT    |  true
COMMON   |  false
SQUAD    |  true
CONFUSE  |  true

Kotlin[edit]

Translation of: Java
object ABC_block_checker {
    fun run() {
        println("\"\": " + blocks.canMakeWord(""))
        for (w in words) println("$w: " + blocks.canMakeWord(w))
    }

    private fun Array<String>.swap(i: Int, j: Int) {
        val tmp = this[i]
        this[i] = this[j]
        this[j] = tmp
    }

    private fun Array<String>.canMakeWord(word: String): Boolean {
        if (word.isEmpty())
            return true

        val c = word.first().toUpperCase()
        var i = 0
        forEach { b ->
            if (b.first().toUpperCase() == c || b[1].toUpperCase() == c) {
                swap(0, i)
                if (drop(1).toTypedArray().canMakeWord(word.substring(1)))
                    return true
                swap(0, i)
            }
            i++
        }

        return false
    }

    private val blocks = arrayOf(
        "BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
        "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"
    )
    private val words = arrayOf("A", "BARK", "book", "treat", "COMMON", "SQuAd", "CONFUSE")
}

fun main(args: Array<String>) = ABC_block_checker.run()
Output:
"": true
A: true
BARK: true
book: false
treat: true
COMMON: false
SQuAd: true
CONFUSE: true

Liberty BASIC[edit]

Recursive solution[edit]

print "Rosetta Code - ABC problem (recursive solution)"
print
blocks$="BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
data "A"
data "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"
data "XYZZY"

do
    read text$
    if text$="XYZZY" then exit do
    print ">>> can_make_word("; chr$(34); text$; chr$(34); ")"
    if canDo(text$,blocks$) then print "True" else print "False"
loop while 1
print "Program complete."
end

function canDo(text$,blocks$)
    'endcase
    if len(text$)=1 then canDo=(instr(blocks$,text$)<>0): exit function
    'get next letter
    ltr$=left$(text$,1)
    'cut
    if instr(blocks$,ltr$)=0 then canDo=0: exit function
    'recursion
    text$=mid$(text$,2) 'rest
    'loop by all word in blocks. Need to make "newBlocks" - all but taken
    'optimisation: take only fitting blocks
    wrd$="*"
    i=0
    while wrd$<>""
        i=i+1
        wrd$=word$(blocks$, i)
        if instr(wrd$, ltr$) then
            'newblocks without wrd$
            pos=instr(blocks$,wrd$)
            newblocks$=left$(blocks$, pos-1)+mid$(blocks$, pos+3)
            canDo=canDo(text$,newblocks$)
            'first found cuts
            if canDo then exit while
        end if
    wend
end function
Output:
Rosetta Code - ABC problem (recursive solution)

>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
>>> can_make_word("SQUAD")
True
>>> can_make_word("CONFUSE")
True
Program complete.

Procedural solution[edit]

print "Rosetta Code - ABC problem (procedural solution)"
print
w$(1)="A"
w$(2)="BARK"
w$(3)="BOOK"
w$(4)="TREAT"
w$(5)="COMMON"
w$(6)="SQUAD"
w$(7)="CONFUSE"

for x=1 to 7
    print ">>> can_make_word("; chr$(34); w$(x); chr$(34); ")"
    if CanMakeWord(w$(x)) then print "True" else print "False"
next x
print "Program complete."
end

function CanMakeWord(x$)
global DoneWithWord, BlocksUsed, LetterOK, Possibility
dim block$(20,2), block(20,2)
'numeric blocks, col 0 flags used block
block(1,1)=asc("B")-64: block(1,2)=asc("O")-64
block(2,1)=asc("X")-64: block(2,2)=asc("K")-64
block(3,1)=asc("D")-64: block(3,2)=asc("Q")-64
block(4,1)=asc("C")-64: block(4,2)=asc("P")-64
block(5,1)=asc("N")-64: block(5,2)=asc("A")-64
block(6,1)=asc("G")-64: block(6,2)=asc("T")-64
block(7,1)=asc("R")-64: block(7,2)=asc("E")-64
block(8,1)=asc("T")-64: block(8,2)=asc("G")-64
block(9,1)=asc("Q")-64: block(9,2)=asc("D")-64
block(10,1)=asc("F")-64: block(10,2)=asc("S")-64
block(11,1)=asc("J")-64: block(11,2)=asc("W")-64
block(12,1)=asc("H")-64: block(12,2)=asc("U")-64
block(13,1)=asc("V")-64: block(13,2)=asc("I")-64
block(14,1)=asc("A")-64: block(14,2)=asc("N")-64
block(15,1)=asc("O")-64: block(15,2)=asc("B")-64
block(16,1)=asc("E")-64: block(16,2)=asc("R")-64
block(17,1)=asc("F")-64: block(17,2)=asc("S")-64
block(18,1)=asc("L")-64: block(18,2)=asc("Y")-64
block(19,1)=asc("P")-64: block(19,2)=asc("C")-64
block(20,1)=asc("Z")-64: block(20,2)=asc("M")-64

x$=upper$(x$)
for x=1 to len(x$)
    y$=mid$(x$,x,1)
    if y$>="A" and y$<="Z" then w$=w$+y$
next x
if w$="" then exit function
DoneWithWord=0: BlocksUsed=0
l=len(w$)
dim LetterOK(l)
dim alphabet(26,1) 'clear letter-usage array
for x=1 to 20 'load block letters into letter-usage array col 0
    alphabet(block(x,1),0)+=1
    alphabet(block(x,2),0)+=1
next x
for x=1 to l 'load current word into letter-usage aray col 1
    wl$=mid$(w$,x,1): w=asc(wl$)-64
    alphabet(w,1)+=1
next x

for x=1 to 26 ' test for more of any letter in the word than in the blocks
    if alphabet(x,1)>alphabet(x,0) then exit function
next x

[NextLetter]
if wl<l then wl=wl+1 else goto [DoneWithWord]
wl$=mid$(w$,wl,1): w=asc(wl$)-64
LetterOK=0
' if there's only one of the letter in the blocks then you must use that block
if alphabet(w,0)=1 then
    call OnlyBlock w
    LetterOK(wl)=1
    if DoneWithWord then goto [DoneWithWord] else goto [NextLetter]
end if
' if more than one of the letter in the blocks, then try to use one that has
' an unused letter on other side (a "Free Block")
call FindFreeBlock w
if LetterOK then LetterOK(wl)=1
goto [NextLetter]

[DoneWithWord]
if BlocksUsed=l then CanMakeWord=1: exit function
if DoneWithWord then exit function
for x=1 to l
    if not(LetterOK(x)) then
        NumericLetter=asc(mid$(w$,x,1))-64
        LetterOK=0
        call OnlyBlock NumericLetter
        if LetterOK then LetterOK(x)=1 else exit for
    end if
next x
goto [DoneWithWord]
end function

sub OnlyBlock NumericLetter
    for x=1 to 20
        if (block(x, 1)=NumericLetter or block(x, 2)=NumericLetter) _
                and block(x, 0)=0 then
            call UseBlock x, NumericLetter
            exit sub
        end if
    next x
    DoneWithWord=1
end sub

sub FindFreeBlock NumericLetter
    Possibility=0
    for x=1 to 20
        if block(x, 0)=0 then 'block not used
            if block(x,1)=NumericLetter then
                if alphabet(block(x,2),1)=0 then
                    call UseBlock x, NumericLetter
                    exit sub
                end if
                Possibility=Possibility+1
            end if
            if block(x,2)=NumericLetter then
                if alphabet(block(x,1),1)=0 then
                    call UseBlock x, NumericLetter
                    exit sub
                end if
                Possibility=Possibility+1
            end if
        end if
    next x
end sub

sub UseBlock BlockNumber, NumericLetter
    block(BlockNumber, 0)=1 'Mark block as used
    BlocksUsed=BlocksUsed+1
    LetterOK=1
end sub
Output:
Rosetta Code - ABC problem (procedural solution)

>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
>>> can_make_word("SQUAD")
True
>>> can_make_word("CONFUSE")
True
Program complete.

[edit]

make "blocks [[B O] [X K] [D Q] [C P] [N A] [G T] [R E] [T G] [Q D] [F S]
              [J W] [H U] [V I] [A N] [O B] [E R] [F S] [L Y] [P C] [Z M]]

to can_make? :word [:avail :blocks]
  if empty? :word [output "true]
  local "letter make "letter first :word
  foreach :avail [
    local "i     make "i     #
    local "block make "block ?
    if member? :letter :block [
      if (can_make? bf :word filter [notequal? # :i] :avail) [output "true]
    ]
  ]
  output "false
end

foreach [A BARK BOOK TREAT COMMON SQUAD CONFUSE] [
  print sentence word ? ": can_make? ?
]

bye
Output:
A: true
BARK: true
BOOK: false
TREAT: true
COMMON: false
SQUAD: true
CONFUSE: true

Lua[edit]

blocks = {
	{"B","O"};	{"X","K"};	{"D","Q"};	{"C","P"};
	{"N","A"};	{"G","T"};	{"R","E"};	{"T","G"};
	{"Q","D"};	{"F","S"};	{"J","W"};	{"H","U"};
	{"V","I"};	{"A","N"};	{"O","B"};	{"E","R"};
	{"F","S"};	{"L","Y"};	{"P","C"};	{"Z","M"};
	};

function canUse(table, letter)
	for i,v in pairs(blocks) do
		if (v[1] == letter:upper() or v[2] == letter:upper())  and table[i] then
			table[i] = false;
			return true;
		end
	end
	return false;
end

function canMake(Word)
	local Taken = {};
	for i,v in pairs(blocks) do
		table.insert(Taken,true);
	end
	local found = true;
	for i = 1,#Word do
		if not canUse(Taken,Word:sub(i,i)) then
			found = false;
		end
	end
	print(found)
end
Output:
canMake("A"): true
canMake("BARK"): true
canMake("BOOK"): false
canMake("TREAT"): true
canMake("COMMON"): false
canMake("SQUAD"): true
canMake("CONFUSE"): true

M2000 Interpreter[edit]

We use a subroutine inside a module. Subs are in the same namespace as the module which call them. Subs may exist in the end of module, or in the parent module (which module defined). We have to use Local to define new variables which shadow any module variable. When a sub exit all new variables which made there erased. Modules run on objects which "interprets" code, and subs use modules objects, so they are lighter than modules. A module hold a separate return stack for subs, gosub and for next structures ( a for {} use process stack, and is twice faster as the simple For Next). This return stack is a stack object, which is a collection of objects in heap, so we can use Recursion.Limit 100000 to set limit to 100000 calls for subs. Here we use a for next and a subroutine, using modules dedicated return stack. We can call can_make_word() using name or using Gosub. Gosub can call subs as labels, and expect Return to return from sub. These routines are more lighter than subs, because they run as code is in module, and any new variable stay until module exit. So we never make local variables or if we want locals we have to use Fopr This { }, the block for temporary definitions.


Module ABC {
      can_make_word("A")
      can_make_word("BaRk")
      can_make_word("BOOK")
      can_make_word("TREAT")
      can_make_word("CommoN")
      can_make_word("SQUAD")
      Gosub can_make_word("CONFUSE")  ' we can use Gosub before
      Sub can_make_word(c$)
            local b$=ucase$(c$)
            local i, a$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM", m
            for i=1 to len(b$)
                  m=Instr(a$,mid$(b$, i, 1))
                  If m=0 Then Exit for
                  Insert binary.or(m-1, 1),2 a$=""   ' delete 2 chars
            Next i
            Print c$, m<>0
      End Sub
}
ABC
Output:
A          True
BaRk       True
BOOK      False
TREAT      True
CommoN    False
SQUAD      True
CONFUSE    True

Maple[edit]

canSpell := proc(w)
	local blocks, i, j, word, letterFound;
	blocks := Array([["B", "O"], ["X", "K"], ["D", "Q"], ["C", "P"], ["N", "A"], ["G", "T"], ["R", "E"], ["T", "G"], 
                         ["Q", "D"], ["F", "S"], ["J", "W"], ["H", "U"], ["V", "I"], ["A", "N"], ["O", "B"], ["E", "R"],
                         ["F", "S"], ["L", "Y"], ["P", "C"], ["Z", "M"]]);
	word := StringTools[UpperCase](convert(w, string));
	for i to length(word) do
		letterFound := false;
		for j to numelems(blocks)/2 do
			if not letterFound and (substring(word, i) = blocks[j,1] or substring(word, i) = blocks[j,2]) then
				blocks[j,1] := undefined;
				blocks[j,2] := undefined;
				letterFound := true;
			end if;
		end do;
		if not letterFound then
			return false;
		end if;
	end do;
	return true;
end proc:

seq(printf("%a: %a\n", i, canSpell(i)), i in [a, Bark, bOok, treat, COMMON, squad, confuse]);
Output:
a: true
Bark: true
bOok: false
treat: true
COMMON: false
squad: true
confuse: true

Mathematica / Wolfram Language[edit]

blocks=Partition[Characters[ToLowerCase["BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"]],2];
ClearAll[DoStep,ABCBlockQ]
DoStep[chars_List,blcks_List,chosen_List]:=Module[{opts},
 If[chars=!={},
  opts=Select[blcks,MemberQ[#,First[chars]]&];
  {Rest[chars],DeleteCases[blcks,#,1,1],Append[chosen,#]}&/@opts
 ,
  {{chars,blcks,chosen}}
 ]
]
DoStep[opts_List]:=Flatten[DoStep@@@opts,1]
ABCBlockQ[str_String]:=(FixedPoint[DoStep,{{Characters[ToLowerCase[str]],blocks,{}}}]=!={})
Output:
ABCBlockQ["A"]
ABCBlockQ["BARK"]
ABCBlockQ["BOOK"]
ABCBlockQ["TREAT"]
ABCBlockQ["COMMON"]
ABCBlockQ["SQUAD"]
ABCBlockQ["CONFUSE"]
True
True
False
True
False
True
True

MATLAB / Octave[edit]

function testABC
    combos = ['BO' ; 'XK' ; 'DQ' ; 'CP' ; 'NA' ; 'GT' ; 'RE' ; 'TG' ; 'QD' ; ...
        'FS' ; 'JW' ; 'HU' ; 'VI' ; 'AN' ; 'OB' ; 'ER' ; 'FS' ; 'LY' ; ...
        'PC' ; 'ZM'];
    words = {'A' 'BARK' 'BOOK' 'TREAT' 'COMMON' 'SQUAD' 'CONFUSE'};
    for k = 1:length(words)
        possible = canMakeWord(words{k}, combos);
        fprintf('Can%s make word %s.\n', char(~possible.*'NOT'), words{k})
    end
end

function isPossible = canMakeWord(word, combos)
    word = lower(word);
    combos = lower(combos);
    isPossible = true;
    k = 1;
    while isPossible && k <= length(word)
        [r, c] = find(combos == word(k), 1);
        if ~isempty(r)
            combos(r, :) = '';
        else
            isPossible = false;
        end
        k = k+1;
    end
end
Output:
Can make word A.
Can make word BARK.
CanNOT make word BOOK.
Can make word TREAT.
CanNOT make word COMMON.
Can make word SQUAD.
Can make word CONFUSE.

MAXScript[edit]

Recursive[edit]

Recursively checks if the word is possible if a block is removed from the array.

-- This is the blocks array
global GlobalBlocks = #("BO","XK","DQ","CP","NA", \
			"GT","RE","TG","QD","FS", \
			"JW","HU","VI","AN","OB", \
			"ER","FS","LY","PC","ZM")

-- This function returns true if "_str" is part of "_word", false otherwise
fn occurs _str _word =
(
	if _str != undefined and _word != undefined then
	(
	matchpattern _word pattern:("*"+_str+"*")
	) else return false
)

-- This is the main function
fn isWordPossible word blocks: = -- blocks is a keyword argument
(
	word = toupper word -- convert the string to upper case, to make it case insensitive
	if blocks == unsupplied do blocks = GlobalBlocks
	-- if blocks (keyword argument) is unsupplied, use the global blocks array (this is for recursion)
	
	blocks = deepcopy blocks

	local pos = 1 -- start at the beginning of the word
	local solvedLetters = #() -- this array stores the indices of solved letters
	
	while pos <= word.count do -- loop through every character in the word
	(
		local possibleBlocks = #() -- this array stores the blocks which can be used to make that letter
		for b = 1 to Blocks.count do -- this loop finds all the possible blocks that can be used to make that letter
		(
			if occurs word[pos] blocks[b] do
			(
				appendifunique possibleBlocks b
			)
		)
		if possibleBlocks.count > 0 then -- if it found any blocks 
		(
			if possibleBlocks.count == 1 then -- if it found one block, then continue
			(
				appendifunique solvedLetters pos
				deleteitem blocks possibleblocks[1]
				pos += 1
			) 
			else -- if it found more than one
			(
				for b = 1 to possibleBlocks.count do -- loop through every possible block
				(
					local possibleBlock = blocks[possibleBlocks[b]]
					local blockFirstLetter = possibleBlock[1]
					local blockSecondLetter = possibleBlock[2]
					local matchingLetter = if blockFirstLetter == word[pos] then 1 else 2
					-- ^ this is the index of the matching letter on the block
					
					local notMatchingIndex = if matchingLetter == 1 then 2 else 1
					local notMatchingLetter = possibleBlock[notMatchingIndex]
					-- ^ this is the other letter on the block
					
					if occurs notMatchingLetter (substring word (pos+1) -1) then
					( -- if the other letter occurs in the rest of the word
						local removedBlocks = deepcopy blocks -- copy the current blocks array
						deleteitem removedBlocks possibleBlocks[b] -- remove the item from the copied array
						
						-- recursively check if the word is possible if that block is taken away from the array:
						if (isWordPossible (substring word (pos+1) -1) blocks:removedBlocks) then 
						( -- if it is, then remove the block and move to next character
							appendifunique solvedLetters pos
							deleteitem blocks possibleblocks[1]
							pos += 1
							exit
						)
						else
						( -- if it isn't and it looped through every possible block, then the word is not possible
							if b == possibleBlocks.count do return false
						)
					)
					else
					( -- if the other letter on this block doesn't occur in the rest of the word, then the letter is solved, continue
							appendifunique solvedLetters pos
							deleteitem blocks possibleblocks[b]
							pos += 1
							exit
					)
				)
			)
		) else return false -- if it didn't find any blocks, then return false
	)

	makeuniquearray solvedLetters -- make sure there are no duplicates in the solved array
	if solvedLetters.count != word.count then return false -- if number of solved letters is not equal to word length
		else 
			( -- this checks if all the solved letters are the same as the word
				check = ""
				for bit in solvedLetters do append check word[bit]
				if check == word then return true else return false
			)
)

Output:

iswordpossible "a"
true
iswordpossible "bark"
true
iswordpossible "book"
false
iswordpossible "treat"
true
iswordpossible "common"
false
iswordpossible "squad"
true
iswordpossible "confuse"
true


Non-recursive[edit]

fn isWordPossible2 word =
(
	Blocks = #("BO","XK","DQ","CP","NA", \
			   "GT","RE","TG","QD","FS", \
			   "JW","HU","VI","AN","OB", \
			   "ER","FS","LY","PC","ZM")
        word = toupper word
	local pos = 1
	local solvedLetters = #()
	while pos <= word.count do
	(
		for i = 1 to blocks.count do
		(
			if (matchpattern blocks[i] pattern:("*"+word[pos]+"*")) then
				(
					deleteitem blocks i
					appendifunique solvedLetters pos
					pos +=1
					exit
				)
			else if i == blocks.count do return false
		)
	)
	if solvedLetters.count == word.count then
	(
		local check = ""
		for bit in solvedLetters do append check word[bit]
		if check == word then return true else return false
	) else return false
)

Both versions are good for this example, but the non-recursive version won't work if the blocks are more random, because it just takes the first found block, and the recursive version decides which one to use. For example, if blocks are: #("RT","WA","WO","TB","RE") Then:

iswordpossible "water"
true
iswordpossible2 "water"
false

Non-recursive version quickly decides that it's not possible, even though it clearly is.

Mercury[edit]

:- module abc.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module list, string, char.

:- type block == {char, char}.

:- pred take(char, list(block), list(block)).
:- mode take(in, in, out) is nondet.
take(C, !Blocks) :-
    list.delete(!.Blocks, {A, B}, !:Blocks),
    ( A = C ; B = C ).

:- pred can_make_word(list(char)::in, list(block)::in) is semidet.
can_make_word([], _).
can_make_word([C|Cs], !.Blocks) :-
    take(C, !Blocks),
    can_make_word(Cs, !.Blocks).

main(!IO) :-
    Blocks = [
        {'B', 'O'}, {'X', 'K'}, {'D', 'Q'}, {'C', 'P'}, {'N', 'A'},
        {'G', 'T'}, {'R', 'E'}, {'T', 'G'}, {'Q', 'D'}, {'F', 'S'},
        {'J', 'W'}, {'H', 'U'}, {'V', 'I'}, {'A', 'N'}, {'O', 'B'},
        {'E', 'R'}, {'F', 'S'}, {'L', 'Y'}, {'P', 'C'}, {'Z', 'M'}
    ],
    Words = ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"],
    foldl((pred(W::in, !.IO::di, !:IO::uo) is det :-
            P = can_make_word(to_char_list(W), Blocks),
            io.format("can_make_word(""%s"") :- %s.\n",
                [s(W), s(if P then "true" else "fail")], !IO)),
        Words, !IO).

Note that 'P', in the foldl near the end, is not a boolean variable, but a zero-arity currying of can_make_word (i.e., it's a 'lambda' that takes no arguments and then calls can_make_word with all of the already-supplied arguments).

MiniScript[edit]

allBlocks = ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"]
 
swap = function(list, index1, index2)
    tmp = list[index1]
    list[index1] = list[index2]
    list[index2] = tmp
end function
 
canMakeWord = function(str, blocks)
    if str == "" then return true
    c = str[0].upper
    for i in range(0, blocks.len - 1)
        bl = blocks[i]
        if c != bl[0] and c != bl[1] then continue
        swap blocks, 0, i
        if canMakeWord(str[1:], blocks[1:]) then return true
        swap blocks, 0, i
    end for
    return false
end function
 
for val in ["", "A", "BARK", "book", "Treat", "COMMON", "sQuAD", "CONFUSE"]
    out = """"""
    if val.len != 0 then out = val
    print out + ": " + canMakeWord(val, allBlocks)
end for

Nim[edit]

Works with: Nim version 0.20.0
import std / strutils

func canMakeWord(blocks: seq[string]; word: string): bool =
    if blocks.len < word.len: return false
    if word.len == 0: return true

    let ch = word[0].toUpperAscii
    for i, pair in blocks:
        if ch in pair and
           (blocks[0..<i] & blocks[i+1..^1]).canMakeWord(word[1..^1]):
            return true

proc main =
    for (blocks, words) in [
        ("BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM".splitWhitespace,
         @["A", "bArK", "BOOK", "treat", "common", "sQuAd", "CONFUSE"]),
        ("AB AB AC AC".splitWhitespace, @["ABBa"]),
        ("US TZ AO QA".splitWhitespace, @["Auto"])
    ]:
        echo "Using the blocks ", blocks.join(" ")
        for word in words:
            echo " can we make the word '$#'? $#" % [
                word, if blocks.canMakeWord(word): "yes" else: "no"]
        echo()

when isMainModule: main()
Output:
Using the blocks BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
 can we make the word 'A'? yes
 can we make the word 'bArK'? yes
 can we make the word 'BOOK'? no
 can we make the word 'treat'? yes
 can we make the word 'common'? no
 can we make the word 'sQuAd'? yes
 can we make the word 'CONFUSE'? yes

Using the blocks AB AB AC AC
 can we make the word 'ABBa'? yes

Using the blocks US TZ AO QA
 can we make the word 'Auto'? yes

Oberon-2[edit]

Works with oo2c Version 2

MODULE ABCBlocks;
IMPORT
  Object,
  Out;

VAR
  blocks: ARRAY 20 OF STRING;
  
    PROCEDURE CanMakeWord(w: STRING): BOOLEAN;
    VAR
      used: ARRAY 20 OF LONGINT;
      wChars: Object.CharsLatin1;
      i,j: LONGINT;

      PROCEDURE IsUsed(i: LONGINT): BOOLEAN;
      VAR
        b: LONGINT;
      BEGIN
        b := 0;
        WHILE (b < LEN(used) - 1) & (used[b] # -1) DO
          IF used[b] = i THEN RETURN TRUE END;
          INC(b)
        END;
        RETURN FALSE
      END IsUsed;

      PROCEDURE GetBlockFor(blocks: ARRAY OF STRING; c: CHAR): LONGINT;
      VAR
        i: LONGINT;
      BEGIN
        i := 0;
        WHILE (i < LEN(blocks)) DO
          IF (blocks[i].IndexOf(c,0) >= 0) & (~IsUsed(i)) THEN RETURN i END;
          INC(i)
        END;
        
        RETURN -1;
      END GetBlockFor;

    BEGIN
      FOR i := 0 TO LEN(used) - 1 DO used[i] := -1 END;
      wChars := w(Object.String8).CharsLatin1();

      i := 0;
      WHILE (i < LEN(wChars^) - 1) DO
        j := GetBlockFor(blocks,CAP(wChars[i]));
        IF j < 0 THEN RETURN FALSE END;
        used[i] := j;
        INC(i)
      END;
      RETURN TRUE
    END CanMakeWord;
  
BEGIN
  blocks[0] := "BO";
  blocks[1] := "XK";
  blocks[2] := "DQ";
  blocks[3] := "CP";
  blocks[4] := "NA";
  blocks[5] := "GT";
  blocks[6] := "RE";
  blocks[7] := "TG";
  blocks[8] := "QD";
  blocks[9] := "FS";
  blocks[10] := "JW";
  blocks[11] := "HU";
  blocks[12] := "VI";
  blocks[13] := "AN";
  blocks[14] := "OB";
  blocks[15] := "ER";
  blocks[16] := "FS";
  blocks[17] := "LY";
  blocks[18] := "PC";
  blocks[19] := "ZM";

  Out.String("A: ");Out.Bool(CanMakeWord("A"));Out.Ln;
  Out.String("BARK: ");Out.Bool(CanMakeWord("BARK"));Out.Ln;
  Out.String("BOOK: ");Out.Bool(CanMakeWord("BOOK"));Out.Ln;
  Out.String("TREAT: ");Out.Bool(CanMakeWord("TREAT"));Out.Ln;
  Out.String("COMMON: ");Out.Bool(CanMakeWord("COMMON"));Out.Ln;
  Out.String("SQAD: ");Out.Bool(CanMakeWord("SQUAD"));Out.Ln;
  Out.String("confuse: ");Out.Bool(CanMakeWord("confuse"));Out.Ln;
END ABCBlocks.

Output:

A: TRUE
BARK: TRUE
BOOK: FALSE
TREAT: TRUE
COMMON: FALSE
SQAD: TRUE
confuse: TRUE

Objeck[edit]

Translation of: Java
class Abc {
  function : Main(args : String[]) ~ Nil {
    blocks := ["BO", "XK", "DQ", "CP", "NA", 
      "GT", "RE", "TG", "QD", "FS", 
      "JW", "HU", "VI", "AN", "OB", 
      "ER", "FS", "LY", "PC", "ZM"];
        
    IO.Console->Print("\"\": ")->PrintLine(CanMakeWord("", blocks));
    IO.Console->Print("A: ")->PrintLine(CanMakeWord("A", blocks));
    IO.Console->Print("BARK: ")->PrintLine(CanMakeWord("BARK", blocks));
    IO.Console->Print("book: ")->PrintLine(CanMakeWord("book", blocks));
    IO.Console->Print("treat: ")->PrintLine(CanMakeWord("treat", blocks));
    IO.Console->Print("COMMON: ")->PrintLine(CanMakeWord("COMMON", blocks));
    IO.Console->Print("SQuAd: ")->PrintLine(CanMakeWord("SQuAd", blocks));
    IO.Console->Print("CONFUSE: ")->PrintLine(CanMakeWord("CONFUSE", blocks));
  }
  
  function : CanMakeWord(word : String, blocks : String[]) ~ Bool {
    if(word->Size() = 0) {
          return true;
    };
 
      c := word->Get(0)->ToUpper();
      for(i := 0; i < blocks->Size(); i++;) {
      b := blocks[i];
      if(<>(b->Get(0)->ToUpper() <> c & b->Get(1)->ToUpper() <> c)) {
        Swap(0, i, blocks);
        new_word := word->SubString(1, word->Size() - 1);
        new_blocks := String->New[blocks->Size() - 1];
        Runtime->Copy(new_blocks, 0, blocks, 1, blocks->Size() - 1);
        if(CanMakeWord(new_word, new_blocks)) {
          return true;
        };
        Swap(0, i, blocks);
      };
    };
    
    return false;
  }
  
  function : native : Swap(i : Int, j : Int, arr : String[]) ~ Nil {
    tmp := arr[i];
    arr[i] := arr[j];
    arr[j] := tmp;
  }
}
"": true
A: true
BARK: true
book: false
treat: true
COMMON: false
SQuAd: true
CONFUSE: true

OCaml[edit]

let blocks = [
  ('B', 'O');  ('X', 'K');  ('D', 'Q');  ('C', 'P');
  ('N', 'A');  ('G', 'T');  ('R', 'E');  ('T', 'G');
  ('Q', 'D');  ('F', 'S');  ('J', 'W');  ('H', 'U');
  ('V', 'I');  ('A', 'N');  ('O', 'B');  ('E', 'R');
  ('F', 'S');  ('L', 'Y');  ('P', 'C');  ('Z', 'M');
]

let find_letter blocks c =
  let found, remaining =
    List.partition (fun (c1, c2) -> c1 = c || c2 = c) blocks
  in
  match found with
  | _ :: res -> Some (res @ remaining)
  | _ -> None

let can_make_word w =
  let n = String.length w in
  let rec aux i _blocks =
    if i >= n then true else
      match find_letter _blocks w.[i] with
      | None -> false
      | Some rem_blocks ->
          aux (succ i) rem_blocks
  in
  aux 0 blocks

let test label f (word, should) =
  Printf.printf "- %s %S = %B  (should: %B)\n" label word (f word) should

let () =
  List.iter (test "can make word" can_make_word) [
    "A", true;
    "BARK", true;
    "BOOK", false;
    "TREAT", true;
    "COMMON", false;
    "SQUAD", true;
    "CONFUSE", true;
  ]
Output:
 $ ocaml canmakeword.ml
 - can make word "A" = true  (should: true)
 - can make word "BARK" = true  (should: true)
 - can make word "BOOK" = false  (should: false)
 - can make word "TREAT" = true  (should: true)
 - can make word "COMMON" = false  (should: false)
 - can make word "SQUAD" = true  (should: true)
 - can make word "CONFUSE" = true  (should: true)

Oforth[edit]

import: mapping

["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS","JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"] 
const: ABCBlocks

: canMakeWord(w, blocks)
| i |
   w empty? ifTrue: [ true return ]
   blocks size loop: i [ 
      w first >upper  blocks at(i) include? ifFalse: [ continue ]
      canMakeWord( w right( w size 1- ), blocks del(i, i) ) ifTrue: [ true return ]
      ]
   false 
;
Output:
["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"] map(#[ ABCBlocks canMakeWord]) .
[1, 1, 0, 1, 0, 1, 1]

OpenEdge/Progress[edit]

FUNCTION canMakeWord RETURNS LOGICAL (INPUT pWord AS CHARACTER) FORWARD.

/* List of blocks */
DEFINE TEMP-TABLE ttBlocks NO-UNDO
    FIELD ttFaces AS CHARACTER FORMAT "x(1)" EXTENT 2
    FIELD ttUsed AS LOGICAL.

/* Fill in list of blocks */
RUN AddBlock("BO").
RUN AddBlock("XK").
RUN AddBlock("DQ").
RUN AddBlock("CP").
RUN AddBlock("NA").
RUN AddBlock("GT").
RUN AddBlock("Re").
RUN AddBlock("TG").
RUN AddBlock("QD").
RUN AddBlock("FS").
RUN AddBlock("JW").
RUN AddBlock("HU").
RUN AddBlock("VI").
RUN AddBlock("AN").
RUN AddBlock("OB").
RUN AddBlock("ER").
RUN AddBlock("FS").
RUN AddBlock("LY").
RUN AddBlock("PC").
RUN AddBlock("ZM").

DEFINE VARIABLE chWords AS CHARACTER EXTENT 7 NO-UNDO.
ASSIGN  chWords[1] = "A"
        chWords[2] = "BARK"
        chWords[3] = "BOOK"
        chWords[4] = "TREAT"
        chWords[5] = "COMMON"
        chWords[6] = "SQUAD"
        chWords[7] = "CONFUSE".

DEFINE FRAME frmResult
    WITH NO-LABELS 7 DOWN USE-TEXT.

DEFINE VARIABLE i AS INTEGER NO-UNDO.
DO i = 1 TO 7:
    DISPLAY chWords[i] + " = " + STRING(canMakeWord(chWords[i])) FORMAT "x(25)" WITH FRAME frmResult.  
    DOWN WITH FRAME frmResult.
END.


PROCEDURE AddBlock:
    DEFINE INPUT PARAMETER i-chBlockvalue AS CHARACTER NO-UNDO.

    IF (LENGTH(i-chBlockValue) <> 2)
        THEN RETURN ERROR.

    CREATE ttBlocks.
    ASSIGN  ttBlocks.ttFaces[1] = SUBSTRING(i-chBlockValue, 1, 1)
            ttBlocks.ttFaces[2] = SUBSTRING(i-chBlockValue, 2, 1).
END PROCEDURE.


FUNCTION blockInList RETURNS LOGICAL (pChar AS CHARACTER):
    /* Find first unused block in list */
    FIND FIRST ttBlocks WHERE (ttBlocks.ttFaces[1] = pChar
                               OR ttBlocks.ttFaces[2] = pChar)
                          AND NOT ttBlocks.ttUsed NO-ERROR.
    IF (AVAILABLE ttBlocks) THEN DO:
        /* found it! set to used and return true */
        ASSIGN ttBlocks.ttUsed = TRUE.
        RETURN TRUE.
    END.
    ELSE RETURN FALSE.
END FUNCTION.


FUNCTION canMakeWord RETURNS LOGICAL (INPUT pWord AS CHARACTER):
    DEFINE VARIABLE i AS INTEGER NO-UNDO.
    DEFINE VARIABLE chChar AS CHARACTER NO-UNDO.

    /* Word has to be valid */
    IF (LENGTH(pWord) = 0) 
        THEN RETURN FALSE.

    DO i = 1 TO LENGTH(pWord):
        /* get the char */
        chChar = SUBSTRING(pWord, i, 1).

        /* Check to see if this is a letter? */
        IF ((ASC(chChar) < 65) OR (ASC(chChar) > 90) AND
            (ASC(chChar) < 97) OR (ASC(chChar) > 122)) 
            THEN RETURN FALSE.

        /* Is block is list (and unused) */
        IF NOT blockInList(chChar)
            THEN RETURN FALSE.
    END.

    /* Reset all blocks */
    FOR EACH ttBlocks:
        ASSIGN ttUsed = FALSE.
    END.
    RETURN TRUE.
END FUNCTION.
Output:
A = yes
BARK = yes
BOOK = no
TREAT = yes
COMMON = no
SQUAD = yes
CONFUSE = yes

Order[edit]

#include <order/interpreter.h>
#include <order/lib.h>

// Because of technical limitations, characters within a "string" must be separated by white spaces.
// For the sake of simplicity, only upper-case characters are supported here.

// A few lines of boiler-plate oriented programming are needed to enable character parsing and comparison.
#define ORDER_PP_TOKEN_A (A)
#define ORDER_PP_TOKEN_B (B)
#define ORDER_PP_TOKEN_C (C)
#define ORDER_PP_TOKEN_D (D)
#define ORDER_PP_TOKEN_E (E)
#define ORDER_PP_TOKEN_F (F)
#define ORDER_PP_TOKEN_G (G)
#define ORDER_PP_TOKEN_H (H)
#define ORDER_PP_TOKEN_I (I)
#define ORDER_PP_TOKEN_J (J)
#define ORDER_PP_TOKEN_K (K)
#define ORDER_PP_TOKEN_L (L)
#define ORDER_PP_TOKEN_M (M)
#define ORDER_PP_TOKEN_N (N)
#define ORDER_PP_TOKEN_O (O)
#define ORDER_PP_TOKEN_P (P)
#define ORDER_PP_TOKEN_Q (Q)
#define ORDER_PP_TOKEN_R (R)
#define ORDER_PP_TOKEN_S (S)
#define ORDER_PP_TOKEN_T (T)
#define ORDER_PP_TOKEN_U (U)
#define ORDER_PP_TOKEN_V (V)
#define ORDER_PP_TOKEN_W (W)
#define ORDER_PP_TOKEN_X (X)
#define ORDER_PP_TOKEN_Y (Y)
#define ORDER_PP_TOKEN_Z (Z)

#define ORDER_PP_SYM_A(...) __VA_ARGS__
#define ORDER_PP_SYM_B(...) __VA_ARGS__
#define ORDER_PP_SYM_C(...) __VA_ARGS__
#define ORDER_PP_SYM_D(...) __VA_ARGS__
#define ORDER_PP_SYM_E(...) __VA_ARGS__
#define ORDER_PP_SYM_F(...) __VA_ARGS__
#define ORDER_PP_SYM_G(...) __VA_ARGS__
#define ORDER_PP_SYM_H(...) __VA_ARGS__
#define ORDER_PP_SYM_I(...) __VA_ARGS__
#define ORDER_PP_SYM_J(...) __VA_ARGS__
#define ORDER_PP_SYM_K(...) __VA_ARGS__
#define ORDER_PP_SYM_L(...) __VA_ARGS__
#define ORDER_PP_SYM_M(...) __VA_ARGS__
#define ORDER_PP_SYM_N(...) __VA_ARGS__
#define ORDER_PP_SYM_O(...) __VA_ARGS__
#define ORDER_PP_SYM_P(...) __VA_ARGS__
#define ORDER_PP_SYM_Q(...) __VA_ARGS__
#define ORDER_PP_SYM_R(...) __VA_ARGS__
#define ORDER_PP_SYM_S(...) __VA_ARGS__
#define ORDER_PP_SYM_T(...) __VA_ARGS__
#define ORDER_PP_SYM_U(...) __VA_ARGS__
#define ORDER_PP_SYM_V(...) __VA_ARGS__
#define ORDER_PP_SYM_W(...) __VA_ARGS__
#define ORDER_PP_SYM_X(...) __VA_ARGS__
#define ORDER_PP_SYM_Y(...) __VA_ARGS__
#define ORDER_PP_SYM_Z(...) __VA_ARGS__

/// 8blocks_lexer (string) : Seq String -> Seq (Seq Sym)
#define ORDER_PP_DEF_8blocks_lexer ORDER_PP_FN \
(8fn (8S \
     ,8seq_map (8tokens_to_seq \
               ,8S \
               ) \
     ) \
)

// Keying the blocks makes filtering them way more efficient than by comparing their letters.
/// 8seq_keyed (sequence) : Seq a -> Seq (Pair Num a)
#define ORDER_PP_DEF_8seq_keyed ORDER_PP_FN \
(8fn (8S \
     ,8stream_to_seq (8stream_pair_with (8pair \
                                        ,8stream_of_naturals \
                                        ,8seq_to_stream (8S) \
                                        ) \
                     ) \
     ) \
)

/// 8abc_internal (blocks, word) : Seq (Pair Num (Seq Token)) -> Seq Token -> Bool
#define ORDER_PP_DEF_8abc_internal ORDER_PP_FN \
(8fn (8B, 8W \
     ,8if (8seq_is_nil (8W) \
          ,8true \
          ,8lets ((8C, 8seq_head (8W)) \
                  (8S, 8seq_filter (8chain (8seq_exists (8same (8C)) \
                                           ,8tuple_at_1 \
                                           ) \
                                   ,8B \
                                   ) \
                  ) \
                  (8T, 8seq_map (8chain (8flip (8seq_filter \
                                               ,8B \
                                               ) \
                                        ,8bin_pr (8not_eq \
                                                 ,8tuple_at_0 \
                                                 ) \
                                        ) \
                                ,8S \
                                ) \
                  ) \
                 ,8seq_exists (8flip (8abc_internal \
                                     ,8seq_tail (8W) \
                                     ) \
                              ,8T \
                              ) \
                 ) \
          ) \
     ) \
)

/// 8abc (blocks, word) : Seq (String) -> String -> Bool
#define ORDER_PP_DEF_8abc ORDER_PP_FN \
(8fn (8B, 8W \
     ,8abc_internal (8seq_keyed (8blocks_lexer (8B)) \
                    ,8tokens_to_seq (8W) \
                    ) \
     ) \
)

#define ORDER_PP_DEF_8blocks ORDER_PP_CONST ( \
    (B O) \
    (X K) \
    (D Q) \
    (C P) \
    (N A) \
    (G T) \
    (R E) \
    (T G) \
    (Q D) \
    (F S) \
    (J W) \
    (H U) \
    (V I) \
    (A N) \
    (O B) \
    (E R) \
    (F S) \
    (L Y) \
    (P C) \
    (Z M) \
)

ORDER_PP
(8seq_map (8step (8pair (8identity
                        ,8abc (8blocks)
                        )
                 )
          ,8quote ((A)
                   (B A R K)
                   (B O O K)
                   (T R E A T)
                   (C O M M O N)
                   (S Q U A D)
                   (C O N F U S E)
                  )
          )
)
Output:
((A,8true))((B A R K,8true))((B O O K,8false))((T R E A T,8true))((C O M M O N,8false))((S Q U A D,8true))((C O N F U S E,8true))

PARI/GP[edit]

BLOCKS = "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM";
WORDS  = ["A","Bark","BOOK","Treat","COMMON","SQUAD","conFUSE"];

can_make_word(w) = check(Vecsmall(BLOCKS), Vecsmall(w))

check(B,W,l=1,n=1) =
{
  if (l > #W, return(1), n > #B, return(0));
  
  forstep (i = 1, #B-2, 2,
    if (B[i] != bitand(W[l],223) && B[i+1] != bitand(W[l],223), next());
    B[i] = B[i+1] = 0;
    if (check(B, W, l+1, n+2), return(1))
  );
  0
}

for (i = 1, #WORDS, printf("%s\t%d\n", WORDS[i], can_make_word(WORDS[i])));
Output:
A	1
Bark	1
BOOK	0
Treat	1
COMMON	0
SQUAD	1
conFUSE	1

Pascal[edit]

Works with: Free Pascal version 2.6.2
#!/usr/bin/instantfpc
//program ABCProblem;

{$mode objfpc}{$H+}

uses SysUtils, Classes;

const
  // every couple of chars is a block
  // remove one by replacing its 2 chars by 2 spaces
  Blocks =  'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM';
  BlockSize = 3;

function can_make_word(Str: String): boolean;
var
  wkBlocks: string = Blocks;
  c: Char;
  iPos : Integer;
begin
  // all chars to uppercase
  Str := UpperCase(Str);
  Result := Str <> '';
  if Result then
  begin
    for c in Str do
    begin
      iPos := Pos(c, wkBlocks);
      if (iPos > 0) then
      begin
        // Char found
        wkBlocks[iPos] := ' ';
        // Remove the other face
        if (iPos mod BlockSize = 1) then
          wkBlocks[iPos + 1] := ' '
        else
          wkBlocks[iPos - 1] := ' ';          
      end
      else
      begin
        //  missed
        Result := False;
        break;
      end;
    end;
  end;
  // Debug...
  //WriteLn(Blocks);
  //WriteLn(wkBlocks);
End;

procedure TestABCProblem(Str: String);
const
  boolStr : array[boolean] of String = ('False', 'True');
begin
  WriteLn(Format('>>> can_make_word("%s")%s%s', [Str, LineEnding, boolStr[can_make_word(Str)]]));
End;

begin
  TestABCProblem('A');
  TestABCProblem('BARK');
  TestABCProblem('BOOK');
  TestABCProblem('TREAT');
  TestABCProblem('COMMON');
  TestABCProblem('SQUAD');
  TestABCProblem('CONFUSE');
END.
Output:
./ABCProblem.pas 
>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
>>> can_make_word("SQUAD")
True
>>> can_make_word("CONFUSE")
True

Perl[edit]

Recursive solution that can handle characters appearing on different blocks:

#!/usr/bin/perl
use warnings;
use strict;


sub can_make_word {
    my ($word, @blocks) = @_;
    $_ = uc join q(), sort split // for @blocks;
    my %blocks;
    $blocks{$_}++ for @blocks;
    return _can_make_word(uc $word, %blocks)
}


sub _can_make_word {
    my ($word, %blocks) = @_;
    my $char = substr $word, 0, 1, q();

    my @candidates = grep 0 <= index($_, $char), keys %blocks;
    for my $candidate (@candidates) {
        next if $blocks{$candidate} <= 0;
        local $blocks{$candidate} = $blocks{$candidate} - 1;
        return 1 if q() eq $word or _can_make_word($word, %blocks);
    }
    return
}

Testing:

use Test::More tests => 8;

my @blocks1 = qw(BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM);
is(can_make_word("A",       @blocks1), 1);
is(can_make_word("BARK",    @blocks1), 1);
is(can_make_word("BOOK",    @blocks1), undef);
is(can_make_word("TREAT",   @blocks1), 1);
is(can_make_word("COMMON",  @blocks1), undef);
is(can_make_word("SQUAD",   @blocks1), 1);
is(can_make_word("CONFUSE", @blocks1), 1);

my @blocks2 = qw(US TZ AO QA);
is(can_make_word('auto', @blocks2), 1);

Regex based alternate[edit]

#!/usr/bin/perl

use strict; # https://rosettacode.org/wiki/ABC_Problem
use warnings;

printf "%30s  %s\n", $_, can_make_word( $_,
  'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM' )
  for qw( A BARK BOOK TREAT COMMON SQUAD CONFUSE );

sub can_make_word
  {
  my ($word, $blocks) = @_;
  my $letter = chop $word or return 'True';
  can_make_word( $word, $` . $' ) eq 'True' and return 'True'
    while $blocks =~ /\w?$letter\w?/gi;
  return 'False';
  }
Output:
                             A  True
                          BARK  True
                          BOOK  False
                         TREAT  True
                        COMMON  False
                         SQUAD  True
                       CONFUSE  True

Phix[edit]

Recursive solution which also solves the extra problems on the discussion page.

sequence blocks, words, used
 
function ABC_Solve(sequence word, integer idx)
integer ch, res = 0
    if idx>length(word) then
        res = 1
-- or:  res = length(word)>0 -- (if "" -> false desired)
    else
        ch = word[idx]
        for k=1 to length(blocks) do
            if used[k]=0
            and find(ch,blocks[k]) then
                used[k] = 1
                res = ABC_Solve(word,idx+1)
                used[k] = 0
                if res then exit end if
            end if
        end for
    end if
    return res
end function
 
constant tests = {{{"BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
                    "JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"},
                   {"","A","BarK","BOOK","TrEaT","COMMON","SQUAD","CONFUSE"}},
                  {{"US","TZ","AO","QA"},{"AuTO"}},
                  {{"AB","AB","AC","AC"},{"abba"}}}
 
for i=1 to length(tests) do
    {blocks,words} = tests[i]
    used = repeat(0,length(blocks))
    for j=1 to length(words) do
        printf(1,"%s: %t\n",{words[j],ABC_Solve(upper(words[j]),1)})
    end for
end for
Output:
: true
A: true
BarK: true
BOOK: false
TrEaT: true
COMMON: false
SQUAD: true
CONFUSE: true
AuTO: true
abba: true

PHP[edit]

<?php
$words = array("A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "Confuse");

function canMakeWord($word) {
    $word = strtoupper($word);
    $blocks = array(
            "BO", "XK", "DQ", "CP", "NA",
            "GT", "RE", "TG", "QD", "FS",
            "JW", "HU", "VI", "AN", "OB",
            "ER", "FS", "LY", "PC", "ZM",
    );

    foreach (str_split($word) as $char) {
        foreach ($blocks as $k => $block) {
            if (strpos($block, $char) !== FALSE) {
                unset($blocks[$k]);
                continue(2);
            }
        }
        return false;
    }
    return true;
}

foreach ($words as $word) {
    echo $word.': ';
    echo canMakeWord($word) ? "True" : "False";
    echo "\r\n";
}
Output:
A: True
BARK: True
BOOK: False
TREAT: True
COMMON: False
SQUAD: True
Confuse: True

Picat[edit]

Showing both a Picat style version (check_word/2) and a Prolog style recursive version (check_word2/2). go2/0 generates all possible solutions (using fail/0) to backtrack.

go =>
  test_it(check_word),
  test_it(check_word2),
  nl.

% Get all possible solutions (via fail)
go2 ?=>
  test_version(check_word2),
  fail,
  nl.
go2 => true.

%
% Test a version.
%
test_it(Pred) =>
  println(testing=Pred),
  Blocks = findall([A,B], block(A,B)),
  Words = findall(W,word(W)),
  foreach(Word in Words)
     println(word=Word),
     ( call(Pred,Word,Blocks) ;  println("Cannot make word.")),
     nl
  end,
  nl.

%
% Picat style: Using nth/3 for getting the chars
%
check_word(Word, Blocks) =>  
  WordC = atom_chars(Word), % convert atom to string
  WordLen = length(WordC),
  X = new_list(WordLen),
  Pos = new_list(WordLen), 
  foreach(I in 1..WordLen)
    % find a character at the specific position
    nth(X[I],Blocks,XI),
    nth(Pos[I],XI, WordC[I])
  end,
  alldiff(X), % ensure unique selection
  foreach(I in 1..WordLen)
    println([WordC[I], Blocks[X[I]]])
  end,
  nl.

%
% Prolog style (recursive) version using select/3.
% (where we don't have to worry about duplicate blocks)
%
check_word2(Word, Blocks) :-
  pick_block(atom_chars(Word),Blocks,[],X),
  println(X).

pick_block([], _,Res,Res).
pick_block([C|WordRest], Blocks, Res1,[Block|Res]) :-
  % pick (non-deterministically) one of the blocks
  select(Block,Blocks,BlocksRest), 
  membchk(C,Block),
  pick_block(WordRest,BlocksRest,Res1,Res).

%
% alldiff(L):
%   ensure that all elements in L are different
%
alldiff([]).
alldiff([_]).
alldiff([H|T]) :-
   neq(H,T),
   alldiff(T).

neq(_,[]).
neq(X,[H|T]) :-
  X != H,
  neq(X,T).

% The words to check.
word(a).
word(bark).
word(book).
word(treat).
word(common).
word(squad).
word(confuse).
word(auto).
word(abba).
word(coestablishment).
word(schoolmastering).

% The blocks
block(b,o).
block(x,k).
block(d,q).
block(c,p).
block(n,a).
block(g,t).
block(r,e).
block(t,g).
block(q,d).
block(f,s).
block(j,w).
block(h,u).
block(v,i).
block(a,n).
block(o,b).
block(e,r).
block(f,s).
block(l,y).
block(p,c).
block(z,m).
Output:
testing = check_word
word = a
[a,na] 

word = bark
[b,bo] [a,na] [r,re] [k,xk] 

word = book
Cannot make word.

word = treat
[t,gt] [r,re] [e,er] [a,na] [t,tg] 

word = common
Cannot make word.

word = squad
[s,fs] [q,dq] [u,hu] [a,na] [d,qd] 

word = confuse
[c,cp] [o,bo] [n,na] [f,fs] [u,hu] [s,fs] [e,re] 

word = auto
[a,na] [u,hu] [t,gt] [o,bo] 

word = abba
[a,na] [b,bo] [b,ob] [a,an] 

word = coestablishment
[c,cp] [o,bo] [e,re] [s,fs] [t,gt] [a,na] [b,ob] [l,ly] [i,vi] [s,fs] [h,hu] [m,zm] [e,er] [n,an] [t,tg] 

word = schoolmastering
[s,fs] [c,cp] [h,hu] [o,bo] [o,ob] [l,ly] [m,zm] [a,na] [s,fs] [t,gt] [e,re] [r,er] [i,vi] [n,an] [g,tg] 

testing = check_word2
word = a
[na]

word = bark
[bo,na,re,xk]

word = book
Cannot make word.

word = treat
[gt,re,er,na,tg]

word = common
Cannot make word.

word = squad
[fs,dq,hu,na,qd]

word = confuse
[cp,bo,na,fs,hu,fs,re]

word = auto
[na,hu,gt,bo]

word = abba
[na,bo,ob,an]

word = coestablishment
[cp,bo,re,fs,gt,na,ob,ly,vi,fs,hu,zm,er,an,tg]

word = schoolmastering
[fs,cp,hu,bo,ob,ly,zm,na,fs,gt,re,er,vi,an,tg]

PicoLisp[edit]

Mapping and recursion.

(setq *Blocks
   '((B O) (X K) (D Q) (C P) (N A) (G T) (R E) 
   (T G) (Q D) (F S) (J W) (H U) (V I) (A N)
   (O B) (E R) (F S) (L Y) (P C) (Z M) ) )
(setq *Words '("" "1" "A" "BARK" "BOOK" "TREAT" 
               "Bbb" "COMMON" "SQUAD" "Confuse"
               "abba" "ANBOCPDQERSFTGUVWXLZ") )
 
(de abc (W B)
   (let Myblocks (copy B)
      (fully
         '((C)
            (when (seek '((Lst) (member C (car Lst))) Myblocks)
               (set @)
               T ) )
      (chop (uppc W)) ) ) )
 
(de abcR (W B)
   (nond
      ((car W) T)
      ((car B) NIL)
      (NIL
         (setq W (chop W))
         (let? I
            (find
               '((Lst) (member (uppc (car W)) Lst))
               B )
            (abcR (cdr W) (delete I B)) ) ) ) )               

(for Word *Words
   (println Word (abc Word *Blocks) (abcR Word *Blocks)) )
    
(bye)

PL/I[edit]

version 1[edit]

ABC: procedure options (main);   /* 12 January 2014 */

   declare word character (20) varying, blocks character (200) varying initial
      ('((B O) (X K) (D Q) (C P) (N A) (G T) (R E) (T G) (Q D) (F S)
        (J W) (H U) (V I) (A N) (O B) (E R) (F S) (L Y) (P C) (Z M))');
   declare tblocks character (200) varying;
   declare (true value ('1'b), false value ('0'b), flag) bit (1);
   declare ch character (1);
   declare (i, k) fixed binary;

   do word = 'A', 'BARK', 'BOOK', 'TREAT', 'COMMON', 'SQuAd', 'CONFUSE';
      flag = true;
      tblocks = blocks;
      do i = 1 to length(word)
      while(flag = true);
         ch = substr(word, i, 1);
         k = index(tblocks, uppercase(ch));
         if k = 0 then
            flag = false;
         else /* Found a block with the letter on it. */
            substr(tblocks, k-1, 4) = '   '; /* Delete the block. */
      end;
      if flag then put skip list (word, 'true'); else put skip list (word, 'false');
   end;

end ABC;
A                       true 
BARK                    true 
BOOK                    false 
TREAT                   true 
COMMON                  false 
SQuAd                   true 
CONFUSE                 true

version 2[edit]

*process source attributes xref or(!) options nest;
 abc: Proc Options(main);
 /* REXX --------------------------------------------------------------
 * 10.01.2013 Walter Pachl  counts the number of possible ways
 * translated from Rexx version 2
 *-------------------------------------------------------------------*/

 Dcl (ADDR,HBOUND,INDEX,LEFT,LENGTH,MAX,SUBSTR,TRANSLATE) builtin;
 Dcl sysprint Print;
 Dcl (i,j,k,m,mm,wi,wj,wlen,ways,lw) Bin Fixed(15);
 Dcl blocks(20) Char(2)
        Init('BO','XK','DQ','CP','NA','GT','RE','TG','QD','FS','JW',
             'HU','VI','AN','OB','ER','FS','LY','PC','ZM');
 Dcl blk Char(2);
 Dcl words(8) Char(7) Var
        Init('$','A','baRk','bOOk','trEat','coMMon','squaD','conFuse');
 Dcl word     Char(7) Var;
 Dcl c Char(1);
 Dcl (show,cannot) Bit(1) Init('0'b);
 Dcl poss(100,0:100) Pic'99';  poss=0;
 Dcl s(20,100) char(100) Var;
 Dcl str Char(100);
 Dcl 1 *(30) Based(addr(str)),
      2 strp Pic'99',
      2 * Char(1);
 Dcl ns(20) Bin Fixed(15) Init((20)0);
 Dcl ol(100) Char(100) Var;
 Dcl os      Char(100) Var;
 wlen=0;
 Dcl lower Char(26) Init('abcdefghijklmnopqrstuvwxyz');
 Dcl upper Char(26) Init('ABCDEFGHIJKLMNOPQRSTUVWXYZ');
 Do wi=1 To hbound(words);
   wlen=max(wlen,length(words(wi)));
   End;
 Do wi=1 To hbound(words);
   word = translate(words(wi),upper,lower);
   ways=0;
   lw=length(word);
   cannot='0'b;
   poss=0;
   ns=0;
   ol='';
 iloop:
   Do i=1 To lw;                       /* loop over the characters   */
     c=substr(word,i,1);               /* the current character      */
     Do j=1 To hbound(blocks);         /* loop over blocks           */
       blk=blocks(j);
       If index(blk,c)>0 Then Do;  /* block can be used in this pos( */
         poss(i,0)+=1;        /* number of possible blocks for pos i */
         poss(i,poss(i,0))=j;
         End;
       End;
     If poss(i,0)=0 Then Do;
       Leave iloop;
       End;
     End;
   If i>lw Then Do;                     /* no prohibitive character  */
     ns=0;
     Do j=1 To poss(1,0);       /* build possible strings for char 1 */
       ns(1)+=1;;
       s(1,j)=poss(1,j);
       End;
     Do m=2 To lw;        /* build possible strings for chars 1 to i */
       mm=m-1;
       Do j=1 To ns(mm);
         Do k=1 To poss(m,0);
           ns(m)+=1;
           s(m,ns(m))=s(mm,j)!!' '!!poss(m,k);
           End;
         End;
       End;
     Do m=1 To ns(lw);
       If valid(s(lw,m)) Then Do;
         ways+=1;
         str=s(lw,m);
         Do k=1 To lw;
           ol(ways)=ol(ways)!!blocks(strp(k))!!' ';
           End;
         End;
       End;
     End;
 /*--------------------------------------------------------------------
 * now show the result
 *-------------------------------------------------------------------*/
   os=left(''''!!word!!'''',wlen+2);
   Select;
     When(ways=0)
       os=os!!' cannot be spelt.';
     When(ways=1)
       os=os!!' can be spelt.';
     Otherwise
       os=os!!' can be spelt in'!!ways!!' ways.';
     End;
   Put Skip List(os);
   If show Then Do;
     Do wj=1 To ways;
       Put Edit('          '!!ol(wj))(Skip,a);
       End;
     End;
   End;
 Return;

 valid: Procedure(list) Returns(bit(1));
 /*--------------------------------------------------------------------
 * Check if the same block is used more than once -> 0
 * Else: the combination is valid
 *-------------------------------------------------------------------*/
 Dcl list Char(*) Var;
 Dcl i Bin Fixed(15);
 Dcl used(20) Bit(1);
 str=list;
 used='0'b;
 Do i=1 To lw;
   If used(strp(i)) Then
     Return('0'b);
   used(strp(i))='1'b;
   End;
 Return('1'b);
 End;

 End;
Output:
'$'       cannot be spelt.
'A'       can be spelt in        2 ways.
'BARK'    can be spelt in        8 ways.
'BOOK'    cannot be spelt.
'TREAT'   can be spelt in        8 ways.
'COMMON'  cannot be spelt.
'SQUAD'   can be spelt in        8 ways.
'CONFUSE' can be spelt in       32 ways.

PL/M[edit]

100H:

/* ABC PROBLEM ON $-TERMINATED STRING */
CAN$MAKE$WORD: PROCEDURE (STRING) BYTE;
    DECLARE STRING ADDRESS, CHAR BASED STRING BYTE;
    DECLARE CONST$BLOCKS DATA 
                ('BOKXDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM');
    DECLARE I BYTE, BLOCKS (40) BYTE;
    
    DO I=0 TO 39; /* MAKE COPY OF BLOCKS */
        BLOCKS(I) = CONST$BLOCKS(I);
    END;
    
    STEP: DO WHILE CHAR <> '$';
        DO I=0 TO 39; /* FIND BLOCK WITH CURRENT CHAR */
            IF BLOCKS(I) = CHAR THEN DO; /* FOUND IT */
                BLOCKS(I) = 0; /* CLEAR OUT BOTH LETTERS ON BLOCK */
                BLOCKS(I XOR 1) = 0;
                STRING = STRING + 1;
                GO TO STEP; /* NEXT CHARACTER */
            END;
        END;
        RETURN 0; /* NO BLOCK WITH LETTER */
    END;
    
    RETURN 1; /* WE FOUND THEM ALL */
END CAN$MAKE$WORD;

/* CP/M BDOS CALL */
BDOS: PROCEDURE (FN, ARG);
    DECLARE FN BYTE, ARG ADDRESS;
    GO TO 5;
END BDOS;

PRINT: PROCEDURE (STRING);
    DECLARE STRING ADDRESS;
    CALL BDOS(9, STRING);
END PRINT;

/* TEST SEVERAL STRINGS */
DECLARE TEST (7) ADDRESS, I BYTE;
TEST(0) = .'A$';
TEST(1) = .'BARK$';
TEST(2) = .'BOOK$';
TEST(3) = .'TREAT$';
TEST(4) = .'COMMON$';
TEST(5) = .'SQUAD$';
TEST(6) = .'CONFUSE$';

DO I = 0 TO LAST(TEST);
    CALL PRINT(TEST(I));
    CALL PRINT(.': $');
    IF CAN$MAKE$WORD(TEST(I))
        THEN CALL PRINT(.'YES$');
        ELSE CALL PRINT(.'NO$');
    CALL PRINT(.(13,10,'$'));
END;

CALL BDOS(0,0);
EOF
Output:
A: YES
BARK: YES
BOOK: NO
TREAT: YES
COMMON: NO
SQUAD: YES
CONFUSE: YES

PowerBASIC[edit]

Works with PowerBASIC 6 Console Compiler

#COMPILE EXE
#DIM ALL
'
' A B C p r o b l e m . b a s
'
' by  Geary Chopoff
' for Chopoff Consulting and RosettaCode.org
' on  2014Jul23
'
'2014Jul23
'
'You are given a collection of ABC blocks. Just like the ones you had when you were a kid.
'There are twenty blocks with two letters on each block. You are guaranteed to have a complete
'alphabet amongst all sides of the blocks. The sample blocks are:
'((B O) (X K) (D Q) (C P) (N A) (G T) (R E) (T G) (Q D) (F S) (J W) (H U) (V I) (A N) (O B) (E R) (F S) (L Y) (P C) (Z M))
'The goal of this task is to write a function that takes a string and can determine whether
'you can spell the word with the given collection of blocks.
'
'The rules are simple:
'1.Once a letter on a block is used that block cannot be used again
'2.The function should be case-insensitive
'3. Show your output on this page for the following words:
'	A, BARK, BOOK, TREAT, COMMON, SQUAD, CONFUSE
'-----------------------------------------------------------------------------
' G l o b a l   C o n s t a n t s
'
%Verbose = 0                'make this 1 to have a lot of feedback
%MAX_BLOCKS = 20            'total number of blocks
%MAX_SIDES = 2              'total number of sides containing a unique letter per block

%MAX_ASC = 255
%FALSE = 0                  'this is correct because there is ONLY ONE value for FALSE
%TRUE  = (NOT %FALSE)       'this is one of MANY values of TRUE!
$FLAG_TRUE = "1"
$FLAG_FALSE = "0"
'-----------------------------------------------------------------------------
' G l o b a l   V a r i a b l e s
'
GLOBAL blk() AS STRING
'-----------------------------------------------------------------------------
'i n i t B l o c k s
'
' as we will use this array only once we build it each time program is run
'
SUB initBlocks
 LOCAL j AS INTEGER
    j=1
    blk(j)="BO"
    j=j+1
    blk(j)="XK"
    j=j+1
    blk(j)="DQ"
    j=j+1
    blk(j)="CP"
    j=j+1
    blk(j)="NA"
    j=j+1
    blk(j)="GT"
    j=j+1
    blk(j)="RE"
    j=j+1
    blk(j)="TG"
    j=j+1
    blk(j)="QD"
    j=j+1
    blk(j)="FS"
    j=j+1
    blk(j)="JW"
    j=j+1
    blk(j)="HU"
    j=j+1
    blk(j)="VI"
    j=j+1
    blk(j)="AN"
    j=j+1
    blk(j)="OB"
    j=j+1
    blk(j)="ER"
    j=j+1
    blk(j)="FS"
    j=j+1
    blk(j)="LY"
    j=j+1
    blk(j)="PC"
    j=j+1
    blk(j)="ZM"
    IF j <> %MAX_BLOCKS THEN
        STDOUT "initBlocks:Error: j is not same as MAX_BLOCKS!",j,%MAX_BLOCKS
    END IF
END SUB
'-----------------------------------------------------------------------------
' m a k e W o r d
'
FUNCTION makeWord(tryWord AS STRING) AS BYTE
 LOCAL retTF AS BYTE
 LOCAL j AS INTEGER
 LOCAL s AS INTEGER         'which side of block we are looking at
 LOCAL k AS INTEGER
 LOCAL c AS STRING          'character in tryWord we are looking for


    FOR j = 1 TO LEN(tryWord)
        c = UCASE$(MID$(tryWord,j,1))   'character we want to show with block

        retTF = %FALSE                  'we assume this will fail

        FOR k = 1 TO %MAX_BLOCKS
            IF LEN(blk(k)) = %MAX_SIDES THEN
                FOR s = 1 TO %MAX_SIDES
                    IF c = MID$(blk(k),s,1) THEN
                        retTF = %TRUE   'this block has letter we want
                        blk(k) = ""     'remove this block from further consideration
                        EXIT FOR
                    END IF
                NEXT s
            END IF
            IF retTF THEN EXIT FOR      'can go on to next character in word
        NEXT k
        IF ISFALSE retTF THEN EXIT FOR  'if character not found then all is done
    NEXT j

    FUNCTION = retTF
END FUNCTION
'-----------------------------------------------------------------------------
' P B M A I N
'
FUNCTION PBMAIN () AS LONG
 DIM blk(1 TO %MAX_BLOCKS, 1 TO %MAX_SIDES) AS STRING
 LOCAL cmdLine AS STRING

    initBlocks              'setup global array of blocks

    cmdLine=COMMAND$
    IF LEN(cmdLine)= 0 THEN
        STDOUT "Useage for ABCproblem Version 1.00:"
        STDOUT ""
        STDOUT "     >ABCproblem tryThisWord"
        STDOUT ""
        STDOUT "Where tryThisWord is a word you want to see if"+STR$(%MAX_BLOCKS)+" blocks can make."
        STDOUT "If word can be made TRUE is returned."
        STDOUT "Otherwise FALSE is returned."
        EXIT FUNCTION
    END IF

    IF INSTR(TRIM$(cmdLine)," ") = 0 THEN
        IF makeWord(cmdLine) THEN
            STDOUT "TRUE"
        ELSE
            STDOUT "FALSE"
        END IF
    ELSE
        STDOUT "Error:Missing word to try to make with blocks!  <" & cmdLine & ">"
        EXIT FUNCTION
    END IF
END FUNCTION
Output:
$ FALSE
A TRUE
bark TRUE
bOOk FALSE
treAT TRUE
COmmon FALSE
sQuaD TRUE
CONFUSE TRUE
GearyChopoff TRUE

PowerShell[edit]

<#
.Synopsis
  ABC Problem
.DESCRIPTION
   You are given a collection of ABC blocks. Just like the ones you had when you were a kid. 
   There are twenty blocks with two letters on each block. You are guaranteed to have a 
   complete alphabet amongst all sides of the blocks
   blocks = "BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS","JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"
   The goal of this task is to write a function that takes a string and can determine whether 
   you can spell the word with the given collection of blocks. 

   The rules are simple: 
        1.Once a letter on a block is used that block cannot be used again 
        2.The function should be case-insensitive 
        3. Show your output on this page for the following words:
        >>> can_make_word("A")
        True
        >>> can_make_word("BARK")
        True
        >>> can_make_word("BOOK")
        False
        >>> can_make_word("TREAT")
        True
        >>> can_make_word("COMMON")
        False
        >>> can_make_word("SQUAD")
        True
        >>> can_make_word("CONFUSE")
        True

   Using the examples below  you can either see just the value or 
   status and the values using the verbose switch

.EXAMPLE
   test-blocks -testword confuse

.EXAMPLE
   test-blocks -testword confuse -verbose

#>

function test-blocks
{
	[CmdletBinding()]
	#  [OutputType([int])]
	Param
	(
		# word to test against blocks
		[Parameter(Mandatory = $true,
				   ValueFromPipelineByPropertyName = $true)]
		$testword
		
	)

	$word = $testword
	
	#define array of blocks
	[System.Collections.ArrayList]$blockarray = "BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"
	
	#send word to chararray
	$chararray = $word.ToCharArray()
	$chars = $chararray
	
	#get the character count
	$charscount = $chars.count
	
	#get the initial count of the blocks
	$blockcount = $blockarray.Count
	
	#find out how many blocks should be left from the difference
	#of the blocks and characters in the word - 1 letter/1 block
	$correctblockcount = $blockcount - $charscount
	
	#loop through the characters in the word
	foreach ($char in $chars)
	{
		
		#loop through the blocks
		foreach ($block in $blockarray)
		{
			
			#check the current character against each letter on the current block
			#and break if found so the array can reload
			if ($char -in $block[0] -or $char -in $block[1])
			{
				
				write-verbose "match for letter - $char - removing block $block"
				$blockarray.Remove($block)
				break
				
			}
			
		}
		
	}
	#get final count of blocks left in array to determine if the word was
	#correctly made
	$finalblockcount = $blockarray.count
	if ($finalblockcount -ne $correctblockcount)
	{
		write-verbose "$word : $false "
		return $false
	}
	else
	{
		write-verbose "$word : $true "
		return $true
	}
	
}

#loop all the words and pass them to the function
$wordlist = "a", "bark", "book", "treat", "common", "squad", "confuse"
foreach ($word in $wordlist)
{
	test-blocks -testword $word -Verbose
}
Output:
VERBOSE: match for letter - a - removing block NA
VERBOSE: a : True 
True
VERBOSE: match for letter - b - removing block BO
VERBOSE: match for letter - a - removing block NA
VERBOSE: match for letter - r - removing block RE
VERBOSE: match for letter - k - removing block XK
VERBOSE: bark : True 
True
VERBOSE: match for letter - b - removing block BO
VERBOSE: match for letter - o - removing block OB
VERBOSE: match for letter - k - removing block XK
VERBOSE: book : False 
False
VERBOSE: match for letter - t - removing block GT
VERBOSE: match for letter - r - removing block RE
VERBOSE: match for letter - e - removing block ER
VERBOSE: match for letter - a - removing block NA
VERBOSE: match for letter - t - removing block TG
VERBOSE: treat : True 
True
VERBOSE: match for letter - c - removing block CP
VERBOSE: match for letter - o - removing block BO
VERBOSE: match for letter - m - removing block ZM
VERBOSE: match for letter - o - removing block OB
VERBOSE: match for letter - n - removing block NA
VERBOSE: common : False 
False
VERBOSE: match for letter - s - removing block FS
VERBOSE: match for letter - q - removing block DQ
VERBOSE: match for letter - u - removing block HU
VERBOSE: match for letter - a - removing block NA
VERBOSE: match for letter - d - removing block QD
VERBOSE: squad : True 
True
VERBOSE: match for letter - c - removing block CP
VERBOSE: match for letter - o - removing block BO
VERBOSE: match for letter - n - removing block NA
VERBOSE: match for letter - f - removing block FS
VERBOSE: match for letter - u - removing block HU
VERBOSE: match for letter - s - removing block FS
VERBOSE: match for letter - e - removing block RE
VERBOSE: confuse : True 
True

or without verbose

True
True
False
True
False
True
True

Prolog[edit]

Traditional[edit]

Works with SWI-Prolog 6.5.3

abc_problem :-
	maplist(abc_problem, ['', 'A', bark, bOOk, treAT, 'COmmon', sQuaD, 'CONFUSE']).


abc_problem(Word) :-
	L = [[b,o],[x,k],[d,q],[c,p],[n,a],[g,t],[r,e],[t,g],[q,d],[f,s],
	     [j,w],[h,u],[v,i],[a,n],[o,b],[e,r],[f,s],[l,y],[p,c],[z,m]],

	(   abc_problem(L, Word)
	->  format('~w OK~n', [Word])
	;   format('~w KO~n', [Word])).

abc_problem(L, Word) :-
	atom_chars(Word, C_Words),
	maplist(downcase_atom, C_Words, D_Words),
	can_makeword(L, D_Words).

can_makeword(_L, []).

can_makeword(L, [H | T]) :-
	(   select([H, _], L, L1); select([_, H], L, L1)),
	can_makeword(L1, T).
Output:
 ?- abc_problem.
 OK
A OK
bark OK
bOOk KO
treAT OK
COmmon KO
sQuaD OK
CONFUSE OK
true.


Constraint Handling Rules[edit]

An approach using [CHR https://dtai.cs.kuleuven.be/CHR/] via SWI-Prolog's [library(chr) http://www.swi-prolog.org/pldoc/man?section=chr] and a module I'm working on for composing predicates composer:

Works with: SWI Prolog 7
:- use_module([ library(chr),
                abathslib(protelog/composer) ]).

:- chr_constraint blocks, block/1, letter/1, word_built.

can_build_word(Word) :-
    maplist(block, [(b,o),(x,k),(d,q),(c,p),(n,a),(g,t),(r,e),(t,g),(q,d),(f,s),
                    (j,w),(h,u),(v,i),(a,n),(o,b),(e,r),(f,s),(l,y),(p,c),(z,m)]),
    maplist(letter) <- string_chars <- string_lower(Word),     %% using the `composer` module
    word_built,
    !.

'take letter and block'  @ letter(L), block((A,B)) <=> L == A ; L == B | true.
'fail if letters remain' @ word_built, letter(_)   <=> false.

%% These rules, removing remaining constraints from the store, are just cosmetic:
'clean up blocks' @ word_built \ block(_) <=> true.
'word was built'  @ word_built            <=> true.


Demonstration:

?- can_build_word("A").
true.
?- can_build_word("BARK").
true.
?- can_build_word("BOOK").
false.
?- can_build_word("TREAT").
true.
?- can_build_word("COMMON").
false.
?- can_build_word("SQUAD").
true.
?- can_build_word("CONFUSE").
true.

PureBasic[edit]

PureBasic: Iterative[edit]

EnableExplicit
#LETTERS = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM "

Procedure.s can_make_word(word.s)
  Define letters.s = #LETTERS, buffer.s
  Define index1.i, index2.i
  Define match.b
  For index1=1 To Len(word)
    index2=1 : match=#False
    Repeat    
      buffer=StringField(letters,index2,Space(1))
      If FindString(buffer,Mid(word,index1,1),1,#PB_String_NoCase)
        letters=RemoveString(letters,buffer+Chr(32),0,1,1)
        match=#True
        Break
      EndIf
      index2+1    
    Until index2>CountString(letters,Space(1))
    If Not match : ProcedureReturn word+#TAB$+"FALSE" : EndIf
  Next
  ProcedureReturn word+#TAB$+"TRUE"
EndProcedure

OpenConsole()
PrintN(can_make_word("a"))
PrintN(can_make_word("BaRK"))
PrintN(can_make_word("BOoK"))
PrintN(can_make_word("TREAt"))
PrintN(can_make_word("cOMMON"))
PrintN(can_make_word("SqUAD"))
PrintN(can_make_word("COnFUSE"))
Input()

PureBasic: Recursive[edit]

#LETTERS = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM "

Macro test(t)
  Print(t+#TAB$+#TAB$+"= ") : If can_make_word(t) : PrintN("True") : Else : PrintN("False") : EndIf
EndMacro

Procedure.s residue(s$,n.i)
  ProcedureReturn Left(s$,Int(n/3)*3)+Mid(s$,Int(n/3)*3+4)
EndProcedure

Procedure.b can_make_word(word$,letters$=#LETTERS)  
  n=FindString(letters$,Left(word$,1),1,#PB_String_NoCase)
  If Len(word$) And n : ProcedureReturn can_make_word(Mid(word$,2),residue(letters$,n)) : EndIf
  If Not Len(word$)   : ProcedureReturn #True : Else : ProcedureReturn #False           : EndIf
EndProcedure

OpenConsole()
test("a")         : test("BaRK")      : test("BOoK")      : test("TREAt")
test("cOMMON")    : test("SqUAD")     : test("COnFUSE")
Input()
Output:
a               = True
BaRK            = True
BOoK            = False
TREAt           = True
cOMMON          = False
SqUAD           = True
COnFUSE         = True

Python[edit]

Python: Iterative, with tests[edit]

'''
Note that this code is broken, e.g., it won't work when 
blocks = [("A", "B"), ("A","C")] and the word is "AB", where the answer
should be True, but the code returns False.
'''
blocks = [("B", "O"),
          ("X", "K"),
          ("D", "Q"),
          ("C", "P"),
          ("N", "A"),
          ("G", "T"),
          ("R", "E"),
          ("T", "G"),
          ("Q", "D"),
          ("F", "S"),
          ("J", "W"),
          ("H", "U"),
          ("V", "I"),
          ("A", "N"),
          ("O", "B"),
          ("E", "R"),
          ("F", "S"),
          ("L", "Y"),
          ("P", "C"),
          ("Z", "M")]


def can_make_word(word, block_collection=blocks):
    """
    Return True if `word` can be made from the blocks in `block_collection`.

    >>> can_make_word("")
    False
    >>> can_make_word("a")
    True
    >>> can_make_word("bark")
    True
    >>> can_make_word("book")
    False
    >>> can_make_word("treat")
    True
    >>> can_make_word("common")
    False
    >>> can_make_word("squad")
    True
    >>> can_make_word("coNFused")
    True
    """
    if not word:
        return False

    blocks_remaining = block_collection[:]
    for char in word.upper():
        for block in blocks_remaining:
            if char in block:
                blocks_remaining.remove(block)
                break
        else:
            return False
    return True


if __name__ == "__main__":
    import doctest
    doctest.testmod()
    print(", ".join("'%s': %s" % (w, can_make_word(w)) for w in
                    ["", "a", "baRk", "booK", "treat", 
                     "COMMON", "squad", "Confused"]))
Output:
'': False, 'a': True, 'baRk': True, 'booK': False, 'treat': True, 'COMMON': False, 'squad': True, 'Confused': True

Python: Recursive[edit]

BLOCKS = 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM'.split()

def _abc(word, blocks):
    for i, ch in enumerate(word):
        for blk in (b for b in blocks if ch in b):
            whatsleft = word[i + 1:]
            blksleft = blocks[:]
            blksleft.remove(blk)
            if not whatsleft: 
                return True, blksleft
            if not blksleft: 
                return False, blksleft
            ans, blksleft = _abc(whatsleft, blksleft)
            if ans:
                return ans, blksleft
        else:
            break
    return False, blocks

def abc(word, blocks=BLOCKS):
    return _abc(word.upper(), blocks)[0]

if __name__ == '__main__':
    for word in [''] + 'A BARK BoOK TrEAT COmMoN SQUAD conFUsE'.split():
        print('Can we spell %9r? %r' % (word, abc(word)))
Output:
Can we spell       ''? False
Can we spell       'A'? True
Can we spell    'BARK'? True
Can we spell    'BoOK'? False
Can we spell   'TrEAT'? True
Can we spell  'COmMoN'? False
Can we spell   'SQUAD'? True
Can we spell 'conFUsE'? True

Python: Recursive, telling how[edit]

def mkword(w, b):
    if not w: return []

    c,w = w[0],w[1:]
    for i in range(len(b)):
        if c in b[i]:
            m = mkword(w, b[0:i] + b[i+1:])
            if m != None: return [b[i]] + m

def abc(w, blk):
    return mkword(w.upper(), [a.upper() for a in blk])

blocks = 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM'.split()

for w in ", A, bark, book, treat, common, SQUAD, conFUsEd".split(', '):
    print '\'' + w + '\'' + ' ->', abc(w, blocks)
Output:

Note the case of empty list returned for empty string; whether it means true or false is up to you.

'' -> []
'A' -> ['NA']
'bark' -> ['BO', 'NA', 'RE', 'XK']
'book' -> None
'treat' -> ['GT', 'RE', 'ER', 'NA', 'TG']
'common' -> None
'SQUAD' -> ['FS', 'DQ', 'HU', 'NA', 'QD']
'conFUsEd' -> ['CP', 'BO', 'NA', 'FS', 'HU', 'FS', 'RE', 'DQ']

q[edit]

The possibility of ‘backtracking’, discussed in the FORTRAN solution above (and not tested by the example set) makes this a classic tree search: wherever there is a choice of blocks from which to pick the next letter, each choice must be tested.

BLOCKS:string`BO`XK`DQ`CP`NA`GT`RE`TG`QD`FS`JW`HU`VI`AN`OB`ER`FS`LY`PC`ZM
WORDS:string`A`BARK`BOOK`TREAT`COMMON`SQUAD`CONFUSE

cmw:{[s;b]                                                   / [str;blocks]
  $[0=count s; 1b;                                           /   empty string
    not any found:any each b=s 0; 0b;                        /   cannot proceed
    any(1_s).z.s/:b(til count b)except/:where found] }
Output:
q)WORDS cmw\:BLOCKS
1101011b

The first expression tests whether the string s is empty. If so, the result is true. This matches two cases: either the string is empty and can be made from any set of blocks; or all its letters have been matched and there is nothing more to check.

The second expression looks in the available blocks b for the first letter of s: the boolean vector found flags any hits. If there are none, the result is false: the string cannot be completed from the available blocks.

The last line searches further. The expression til count b indexes the remaining blocks; and where found are the indexes that have the next letter. The derived function except/: yields a list: each item is a copy of the list of indexes til count b, with one of the found indexes removed. The list of blocks b is applied to each of these index lists; the result is multiple versions of the list of blocks; each has had a different block removed. The cmw function is applied to each of these with the truncated string 1_s. (The expression .z.s refers to the currently-running function, so cmw does not need to know its own name.) The result of these calls is a boolean vector; aggregator any reports if any have succeeded in completing the string.

To meet the requirement for case-insensitivity and to display the results, apply the above within a wrapper.

Words:string`A`bark`BOOK`Treat`COMMON`squad`CONFUSE
cmwi:{(`$x), `false`true cmw . upper each(x;y) }
Output:
q)Words cmwi\:BLOCKS
A       true
bark    true
BOOK    false
Treat   true
COMMON  false
squad   true
CONFUSE true

Quackery[edit]

Iterative, without backtracking[edit]

See note in the FORTRAN solution and elsewhere re: backtracking. Fails the ABBA test, see "Greedy Algorithm" in the discussion for this page.

This solution assumes the constraint that if a letter appears on more than one block those blocks are identical (as in the example set) so backtracking is not required.

[ $ "BOXKDQCPNAGTRETGQDFS"
  $ "JWHUVIANOBERFSLYPCZM"
  join ] constant          is blocks        (     --> $ )

[ -2 &
  tuck pluck drop
  swap pluck drop ]        is remove2       ( $ n --> $ )

[ iff [ say "True" ]
  else [ say "False" ] ]   is echotruth     (   b -->   )

[ true blocks rot
  witheach
    [ upper over find
      2dup swap found 
      iff remove2
      else 
        [ drop dip not 
          conclude ] ]
  drop echotruth ]        is can_make_word (   $ -->   )

Testing in the Quackery shell:

/O> $ "A" can_make_word
... 
True
Stack empty.

/O> $ "BARK" can_make_word
... 
True
Stack empty.

/O> $ "BOOK" can_make_word
... 
False
Stack empty.

/O> $ "TREAT" can_make_word
... 
True
Stack empty.

/O> $ "COMMON" can_make_word
... 
False
Stack empty.

/O> $ "SQUAD" can_make_word
... 
True
Stack empty.

/O> $ "CONFUSE" can_make_word
... 
True
Stack empty.

Recursive, with backtracking[edit]

See note in the FORTRAN solution and elsewhere re: backtracking. Passes the ABBA test, see "Greedy Algorithm" in the discussion for this page.

This solution does not assume the constraint that if a letter appears on more than one block those blocks are identical (as in the example set) so backtracking is required.

[ ' [ 0 ] swap
  witheach
    [ over -1 peek
      + join ]
  behead drop ]            is accumulate    (   [ --> [ )

[ [] swap
  witheach
    [ swap dip
        [ over + ]
      swap join ]
   nip ]                   is add           ( n [ --> [ )

[ [] unrot
  [ 2dup find
    2dup swap
    found while
    1+ split
    swap size
    dip rot join
    unrot again ]
  2drop drop
  accumulate
  -1 swap add ]            is findall       ( x [ --> [ )

[ iff [ say "True" ]
  else [ say "False" ] ]   is echotruth     (   b -->   )

[ $ "BOXKDQCPNAGTRETGQDFS"
  $ "JWHUVIANOBERFSLYPCZM"
  join ] constant          is blocks        (     --> $ )

[ -2 &
  tuck pluck drop
  swap pluck drop ]        is remove2       ( $ n --> $ )

                   forward is (abc)

[ dup [] = if bail
  behead upper
  dip over swap findall
  witheach
    [ dip over
      remove2
      over (abc) ]
  2drop ]            resolves (abc)         ( $ $ -->   )

[ blocks swap
  2 backup (abc)
  bailed dup 
  if [ dip 2drop ]
  echotruth ]              is can_make_word (   $ -->   )

Testing in the Quackery shell: Identical to iterative solution above.

R[edit]

With recursion[edit]

Vectorised function for R which will take a character vector and return a logical vector of equal length with TRUE and FALSE as appropriate for words which can/cannot be made with the blocks.

blocks <- rbind(c("B","O"),
 c("X","K"), 
 c("D","Q"), 
 c("C","P"), 
 c("N","A"), 
 c("G","T"), 
 c("R","E"), 
 c("T","G"), 
 c("Q","D"), 
 c("F","S"), 
 c("J","W"), 
 c("H","U"), 
 c("V","I"), 
 c("A","N"), 
 c("O","B"), 
 c("E","R"), 
 c("F","S"), 
 c("L","Y"), 
 c("P","C"), 
 c("Z","M"))

canMake <- function(x) {
  x <- toupper(x)
  used <- rep(FALSE, dim(blocks)[1L])
  charList <- strsplit(x, character(0))
  tryChars <- function(chars, pos, used, inUse=NA) {
    if (pos > length(chars)) {
      TRUE
    } else {
      used[inUse] <- TRUE
      possible <- which(blocks == chars[pos] & !used, arr.ind=TRUE)[, 1L]
      any(vapply(possible, function(possBlock) tryChars(chars, pos + 1, used, possBlock), logical(1)))
    }
  }
  setNames(vapply(charList, tryChars, logical(1), 1L, used), x)
}
canMake(c("A",
           "BARK",
           "BOOK",
           "TREAT",
           "COMMON",
           "SQUAD",
           "CONFUSE"))
Output:
      A    BARK    BOOK   TREAT  COMMON   SQUAD CONFUSE 
   TRUE    TRUE   FALSE    TRUE   FALSE    TRUE    TRUE

Without recursion[edit]

Second version without recursion and giving every unique combination of blocks for each word:

canMakeNoRecursion <- function(x) {
  x <- toupper(x)
  charList <- strsplit(x, character(0))
  getCombos <- function(chars) {
    charBlocks <-  data.matrix(expand.grid(lapply(chars, function(char) which(blocks == char, arr.ind=TRUE)[, 1L])))
    charBlocks <- charBlocks[!apply(charBlocks, 1, function(row) any(duplicated(row))), , drop=FALSE]
    if (dim(charBlocks)[1L] > 0L) {
      t(apply(charBlocks, 1, function(row) apply(blocks[row, , drop=FALSE], 1, paste, collapse="")))
    } else {
      character(0)
    }
  }
  setNames(lapply(charList, getCombos), x)
}
canMakeNoRecursion(c("A",
           "BARK",
           "BOOK",
           "TREAT",
           "COMMON",
           "SQUAD",
           "CONFUSE"))
Output:
$A
     [,1] [,2]
[1,] "AN" "NA"

$BARK
     [,1] [,2] [,3] [,4]
[1,] "BO" "AN" "RE" "XK"
[2,] "OB" "AN" "RE" "XK"
[3,] "BO" "NA" "RE" "XK"
[4,] "OB" "NA" "RE" "XK"
[5,] "BO" "AN" "ER" "XK"
[6,] "OB" "AN" "ER" "XK"
[7,] "BO" "NA" "ER" "XK"
[8,] "OB" "NA" "ER" "XK"

$BOOK
character(0)

$TREAT
     [,1] [,2] [,3] [,4] [,5]
[1,] "GT" "RE" "ER" "AN" "TG"
[2,] "GT" "ER" "RE" "AN" "TG"
[3,] "GT" "RE" "ER" "NA" "TG"
[4,] "GT" "ER" "RE" "NA" "TG"
[5,] "TG" "RE" "ER" "AN" "GT"
[6,] "TG" "ER" "RE" "AN" "GT"
[7,] "TG" "RE" "ER" "NA" "GT"
[8,] "TG" "ER" "RE" "NA" "GT"

$COMMON
character(0)

$SQUAD
     [,1] [,2] [,3] [,4] [,5]
[1,] "FS" "QD" "HU" "AN" "DQ"
[2,] "FS" "QD" "HU" "AN" "DQ"
[3,] "FS" "QD" "HU" "NA" "DQ"
[4,] "FS" "QD" "HU" "NA" "DQ"
[5,] "FS" "DQ" "HU" "AN" "QD"
[6,] "FS" "DQ" "HU" "AN" "QD"
[7,] "FS" "DQ" "HU" "NA" "QD"
[8,] "FS" "DQ" "HU" "NA" "QD"

$CONFUSE
      [,1] [,2] [,3] [,4] [,5] [,6] [,7]
 [1,] "CP" "OB" "NA" "FS" "HU" "FS" "ER"
 [2,] "PC" "OB" "NA" "FS" "HU" "FS" "ER"
 [3,] "CP" "BO" "NA" "FS" "HU" "FS" "ER"
 [4,] "PC" "BO" "NA" "FS" "HU" "FS" "ER"
 [5,] "CP" "OB" "AN" "FS" "HU" "FS" "ER"
 [6,] "PC" "OB" "AN" "FS" "HU" "FS" "ER"
 [7,] "CP" "BO" "AN" "FS" "HU" "FS" "ER"
 [8,] "PC" "BO" "AN" "FS" "HU" "FS" "ER"
 [9,] "CP" "OB" "NA" "FS" "HU" "FS" "ER"
[10,] "PC" "OB" "NA" "FS" "HU" "FS" "ER"
[11,] "CP" "BO" "NA" "FS" "HU" "FS" "ER"
[12,] "PC" "BO" "NA" "FS" "HU" "FS" "ER"
[13,] "CP" "OB" "AN" "FS" "HU" "FS" "ER"
[14,] "PC" "OB" "AN" "FS" "HU" "FS" "ER"
[15,] "CP" "BO" "AN" "FS" "HU" "FS" "ER"
[16,] "PC" "BO" "AN" "FS" "HU" "FS" "ER"
[17,] "CP" "OB" "NA" "FS" "HU" "FS" "RE"
[18,] "PC" "OB" "NA" "FS" "HU" "FS" "RE"
[19,] "CP" "BO" "NA" "FS" "HU" "FS" "RE"
[20,] "PC" "BO" "NA" "FS" "HU" "FS" "RE"
[21,] "CP" "OB" "AN" "FS" "HU" "FS" "RE"
[22,] "PC" "OB" "AN" "FS" "HU" "FS" "RE"
[23,] "CP" "BO" "AN" "FS" "HU" "FS" "RE"
[24,] "PC" "BO" "AN" "FS" "HU" "FS" "RE"
[25,] "CP" "OB" "NA" "FS" "HU" "FS" "RE"
[26,] "PC" "OB" "NA" "FS" "HU" "FS" "RE"
[27,] "CP" "BO" "NA" "FS" "HU" "FS" "RE"
[28,] "PC" "BO" "NA" "FS" "HU" "FS" "RE"
[29,] "CP" "OB" "AN" "FS" "HU" "FS" "RE"
[30,] "PC" "OB" "AN" "FS" "HU" "FS" "RE"
[31,] "CP" "BO" "AN" "FS" "HU" "FS" "RE"
[32,] "PC" "BO" "AN" "FS" "HU" "FS" "RE"

Racket[edit]

I believe you can make an empty word by using no blocks. So '(can-make-word? "")' is true for me.

#lang racket
(define block-strings
  (list "BO" "XK" "DQ" "CP" "NA"
        "GT" "RE" "TG" "QD" "FS"
        "JW" "HU" "VI" "AN" "OB"
        "ER" "FS" "LY" "PC" "ZM"))
(define BLOCKS (map string->list block-strings))

(define (can-make-word? w)
  (define (usable-block blocks word-char)
    (for/first ((b (in-list blocks)) #:when (memf (curry char-ci=? word-char) b)) b))
  
  (define (inner word-chars blocks tried-blocks)
    (cond
      [(null? word-chars) #t]
      [(usable-block blocks (car word-chars))
       =>
       (lambda (b)
         (or
          (inner (cdr word-chars) (append tried-blocks (remove b blocks)) null)
          (inner word-chars (remove b blocks) (cons b tried-blocks))))]
      [else #f]))
  (inner (string->list w) BLOCKS null))

(define WORD-LIST '("" "A" "BARK" "BOOK" "TREAT" "COMMON" "SQUAD" "CONFUSE"))
(define (report-word w)
  (printf "Can we make: ~a? ~a~%"
          (~s w #:min-width 9)
          (if (can-make-word? w) "yes" "no")))

(module+ main
  (for-each report-word WORD-LIST))  

(module+ test
  (require rackunit)
  (check-true  (can-make-word? ""))
  (check-true  (can-make-word? "A"))
  (check-true  (can-make-word? "BARK"))
  (check-false (can-make-word? "BOOK"))
  (check-true  (can-make-word? "TREAT"))
  (check-false (can-make-word? "COMMON"))
  (check-true  (can-make-word? "SQUAD"))
  (check-true  (can-make-word? "CONFUSE")))
Output:
Can we make: ""       ? yes
Can we make: "A"      ? yes
Can we make: "BARK"   ? yes
Can we make: "BOOK"   ? no
Can we make: "TREAT"  ? yes
Can we make: "COMMON" ? no
Can we make: "SQUAD"  ? yes
Can we make: "CONFUSE"? yes

Raku[edit]

(formerly Perl 6)

Works with: rakudo version 6.0.c

Blocks are stored as precompiled regexes. We do an initial pass on the blockset to include in the list only those regexes that match somewhere in the current word. Conveniently, regexes scan the word for us.

multi can-spell-word(Str $word, @blocks) {
    my @regex = @blocks.map({ my @c = .comb; rx/<@c>/ }).grep: { .ACCEPTS($word.uc) }
    can-spell-word $word.uc.comb.list, @regex;
}
 
multi can-spell-word([$head,*@tail], @regex) {
    for @regex -> $re {
        if $head ~~ $re {
            return True unless @tail;
            return False if @regex == 1;
            return True if can-spell-word @tail, list @regex.grep: * !=== $re;
        }
    }
    False;
}
 
my @b = <BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM>;
 
for <A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE> {
    say "$_     &can-spell-word($_, @b)";
}
Output:
A	True
BaRK	True
BOoK	False
tREaT	True
COmMOn	False
SqUAD	True
CoNfuSE	True

RapidQ[edit]

dim Blocks as string
dim InWord as string

Function CanMakeWord (FInWord as string, FBlocks as string) as integer
    dim WIndex as integer, BIndex as integer
    
    FBlocks = UCase$(FBlocks) - " " - ","
    FInWord = UCase$(FInWord)
    
    for WIndex = 1 to len(FInWord)
        BIndex = instr(FBlocks, FInWord[WIndex])
        
        if BIndex then
            FBlocks = Replace$(FBlocks,"**",iif(BIndex mod 2,BIndex,BIndex-1))
        else
            Result = 0
            exit function
        end if
    next
    
    Result = 1            
end function 

InWord = "Confuse"
Blocks = "BO, XK, DQ, CP, NA, GT, RE, TG, QD, FS, JW, HU, VI, AN, OB, ER, FS, LY, PC, ZM"
showmessage "Can make: " + InWord + " = " + iif(CanMakeWord(InWord, Blocks), "True", "False")
Output:
Can make: A = TRUE
Can make: BARK = TRUE
Can make: BOOK = FALSE
Can make: TREAT = TRUE
Can make: COMMON = FALSE
Can make: SQUAD = TRUE
Can make: CONFUSE = TRUE

Red[edit]

Red []
test: func [ s][
p: copy "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
forever [
    if 0 = length? s [  return  'true   ]               ;; if string cleared, all chars found/removed
    if tail? p  [  return 'false   ]                      ;; if at end of search block - not found
    rule: reduce [  first p  '| second p]                 ;; construct parse rule from string
    either parse s [  to rule remove rule to end ] [    ;; remove found char from string
      remove/part p 2                                     ;;character found , remove block
      p: head p                                             ;;start from remaining string at beginning aka head 
    ] [  p: skip p 2  ]                                      ;; else move to next block
]
]
foreach word split {A bark book TrEAT COmMoN SQUAD conFUsE}  space [
  print reduce [ pad copy word 8 ":" test word]
 ]
Output:
A        : true
bark     : true
book     : false
TrEAT    : true
COmMoN   : false
SQUAD    : true
conFUsE  : true

REXX[edit]

version 1[edit]

/*REXX pgm finds if words can be spelt from a pool of toy blocks (each having 2 letters)*/
list= 'A bark bOOk treat common squaD conFuse'   /*words can be:  upper/lower/mixed case*/
blocks= 'BO  XK  DQ  CP  NA  GT  RE  TG  QD  FS  JW  HU  VI  AN  OB  ER  FS  LY  PC  ZM'
              do k=1  for  words(list)           /*traipse through a list of some words.*/
              call  spell  word(list, k)         /*display if word can be spelt (or not)*/
              end   /*k*/                        /* [↑]  tests each word in the list.   */
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
spell: procedure expose blocks;  arg x           /*ARG  uppercases the word to be spelt.*/
                         L= length(x);   @.= 0   /*get length of the word to be spelt.  */
           do try=1  for L;  z= blocks;  upper z /*use a fresh copy of the  "Z"  blocks.*/
             do n=1  for L;  y= substr(x, n, 1)  /*attempt another letter in the word.  */
             @.n= pos(y, z, 1 + @.n);    if @.n==0  then leave   /*not found?  Try again*/
             z= overlay(' ', z, @.n)             /*mutate the toy block  ───►  a onesy. */
                do q=1  for words(z);    if length(word(z,q))==1  then z= delword(z, q, 1)
                end   /*q*/                      /* [↑]  elide any existing onesy block.*/
             if n==L  then leave try             /*was last letter used in the spelling?*/
             end      /*n*/                      /* [↑]  end of a  toy block  usage.    */
           end        /*try*/                    /* [↑]  end of a  "TRY"  permute.      */
       say right( arg(1), 30)    right( word( "can't can", (n==L) + 1), 6)     'be spelt.'
       return
output   when using the default inputs:
                             A    can be spelt.
                          bark    can be spelt.
                          bOOk  can't be spelt.
                         treat    can be spelt.
                        common  can't be spelt.
                         squaD    can be spelt.
                       conFuse    can be spelt.  

version 2[edit]

/* REXX ---------------------------------------------------------------
* 10.01.2014 Walter Pachl  counts the number of possible ways
* 12.01.2014 corrected date and output
*--------------------------------------------------------------------*/
show=(arg(1)<>'')
blocks = 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM'
list = '$ A baRk bOOk trEat coMMon squaD conFuse'
list=translate(list)
Do i=1 To words(blocks)
  blkn.i=word(blocks,i)'-'i
  blk.i=word(blocks,i)
  End
w.=''
wlen=0
Do i=1 To words(list)
  w.i=word(list,i)
  wlen=max(wlen,length(w.i))
  End
Do wi=0 To words(list)
  word = w.wi
  ways=0
  poss.=0
  lw=length(word)
  cannot=0
  Do i=1 To lw                         /* loop over the characters   */
    c=substr(word,i,1)                 /* the current character      */
    Do j=1 To words(blocks)            /* loop over blocks           */
      blk=word(blocks,j)
      If pos(c,blk)>0 Then Do  /* block can be used in this position */
        z=poss.i.0+1
        poss.i.z=j
        poss.i.0=z            /* number of possible blocks for pos i */
        End
      End
    If poss.i.0=0 Then Do
      cannot=1
      Leave i
      End
    End

  If cannot=0 Then Do                  /* no prohibitive character   */
    s.=0
    Do j=1 To poss.1.0          /* build possible strings for char 1 */
      z=s.1.0+1
      s.1.z=poss.1.j
      s.1.0=z
      End
    Do i=2 To lw          /* build possible strings for chars 1 to i */
      ii=i-1
      Do j=1 To poss.i.0
        Do k=1 To s.ii.0
          z=s.i.0+1
          s.i.z=s.ii.k poss.i.j
          s.i.0=z
          End
        End
      End
    Do p=1 To s.lw.0            /* loop through all possible strings */
      v=valid(s.lw.p)                  /* test if the string is valid*/
      If v Then Do                     /* it is                      */
        ways=ways+1                    /* increment number of ways   */
        way.ways=''                 /* and store the string's blocks */
        Do ii=1 To lw
          z=word(s.lw.p,ii)
          way.ways=way.ways blk.z
          End
        End
      End
    End
/*---------------------------------------------------------------------
* now show the result
*--------------------------------------------------------------------*/
  ol=left(''''word'''',wlen+2)
  Select
    When ways=0 Then
      ol=ol 'cannot be spelt'
    When ways=1 Then
      ol=ol 'can be spelt'
    Otherwise
      ol=ol 'can be spelt in' ways 'ways'
    End
  Say ol'.'
  If show Then Do
    Do wj=1 To ways
      Say copies(' ',10) way.wj
      End
    End
  End
Exit

valid: Procedure
/*---------------------------------------------------------------------
* Check if the same block is used more than once -> 0
* Else: the combination is valid
*--------------------------------------------------------------------*/
  Parse Arg list
  used.=0
  Do i=1 To words(list)
    w=word(list,i)
    If used.w Then Return 0
    used.w=1
    End
  Return 1
Output:
''        cannot be spelt.
'$'       cannot be spelt.
'A'       can be spelt in 2 ways.
'BARK'    can be spelt in 8 ways.
'BOOK'    cannot be spelt.
'TREAT'   can be spelt in 8 ways.
'COMMON'  cannot be spelt.
'SQUAD'   can be spelt in 8 ways.
'CONFUSE' can be spelt in 32 ways.
Output:
extended
''        cannot be spelt.
'$'       cannot be spelt.
'A'       can be spelt in 2 ways.
            NA
            AN
'BARK'    can be spelt in 8 ways.
            BO NA RE XK
            OB NA RE XK
            BO AN RE XK
            OB AN RE XK
            BO NA ER XK
            OB NA ER XK
            BO AN ER XK
            OB AN ER XK
'BOOK'    cannot be spelt.
'TREAT'   can be spelt in 8 ways.
            TG ER RE NA GT
            TG RE ER NA GT
            TG ER RE AN GT
            TG RE ER AN GT
            GT ER RE NA TG
            GT RE ER NA TG
            GT ER RE AN TG
            GT RE ER AN TG
'COMMON'  cannot be spelt.
'SQUAD'   can be spelt in 8 ways.
            FS QD HU NA DQ
            FS QD HU NA DQ
            FS QD HU AN DQ
            FS QD HU AN DQ
            FS DQ HU NA QD
            FS DQ HU NA QD
            FS DQ HU AN QD
            FS DQ HU AN QD
'CONFUSE' can be spelt in 32 ways.
            CP BO NA FS HU FS RE
            PC BO NA FS HU FS RE
            CP OB NA FS HU FS RE
            PC OB NA FS HU FS RE
            CP BO AN FS HU FS RE
            PC BO AN FS HU FS RE
            CP OB AN FS HU FS RE
            PC OB AN FS HU FS RE
            CP BO NA FS HU FS RE
            PC BO NA FS HU FS RE
            CP OB NA FS HU FS RE
            PC OB NA FS HU FS RE
            CP BO AN FS HU FS RE
            PC BO AN FS HU FS RE
            CP OB AN FS HU FS RE
            PC OB AN FS HU FS RE
            CP BO NA FS HU FS ER
            PC BO NA FS HU FS ER
            CP OB NA FS HU FS ER
            PC OB NA FS HU FS ER
            CP BO AN FS HU FS ER
            PC BO AN FS HU FS ER
            CP OB AN FS HU FS ER
            PC OB AN FS HU FS ER
            CP BO NA FS HU FS ER
            PC BO NA FS HU FS ER
            CP OB NA FS HU FS ER
            PC OB NA FS HU FS ER
            CP BO AN FS HU FS ER
            PC BO AN FS HU FS ER
            CP OB AN FS HU FS ER
            PC OB AN FS HU FS ER

Ring[edit]

Blocks = [ :BO, :XK, :DQ, :CP, :NA, :GT, :RE, :TG, :QD, :FS, :JW, :HU, :VI, :AN, :OB, :ER, :FS, :LY, :PC, :ZM ]
Words = [ :A, :BARK, :BOOK, :TREAT, :COMMON, :SQUAD, :CONFUSE ]

for x in words
see '>>> can_make_word("' + upper(x) + '")' + nl 
if checkword(x,blocks) see "True" + nl
else see "False" + nl
ok
next

func CheckWord Word,Blocks
cBlocks = BLocks
for x in word 
Found = false
for y = 1 to len(cblocks)
if x = cblocks[y][1] or x = cblocks[y][2]
cblocks[y] = "--"
found = true
exit
ok
next
if found = false return false ok
next
return true
Output:
>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
>>> can_make_word("SQUAD")
True
 >>> can_make_word("CONFUSE")
True

Ruby[edit]

This one uses a case insensitive regular expression. The 'sub!' method substitutes the first substring it finds and returns nil if nothing is found.

words = %w(A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE) << ""

words.each do |word|
  blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
  res = word.each_char.all?{|c| blocks.sub!(/\w?#{c}\w?/i, "")}  #regexps can be interpolated like strings
  puts "#{word.inspect}: #{res}"
end
Output:
"A": true
"BaRK": true
"BOoK": false
"tREaT": true
"COmMOn": false
"SqUAD": true
"CoNfuSE": true
"": true

Run BASIC[edit]

blocks$    = "BO,XK,DQ,CP,NA,GT,RE,TG,QD,FS,JW,HU,VI,AN,OB,ER,FS,LY,PC,ZM"
makeWord$  = "A,BARK,BOOK,TREAT,COMMON,SQUAD,Confuse"
b          = int((len(blocks$) /3) +  1)
dim blk$(b)
 
for i = 1 to len(makeWord$)
  wrd$ = word$(makeWord$,i,",")
  dim hit(b)
  n = 0
  if wrd$ = "" then exit for
  for k = 1 to len(wrd$)
    w$ = upper$(mid$(wrd$,k,1))
    for j = 1 to b
     if hit(j) = 0 then
      if w$ = left$(word$(blocks$,j,","),1) or w$ = right$(word$(blocks$,j,","),1) then
        hit(j) = 1
        n = n + 1
        exit for
      end if
     end if
    next j
  next k
  print wrd$;chr$(9);
  if n = len(wrd$) then print " True" else print " False"
next i
A	 True
BARK	 True
BOOK	 False
TREAT	 True
COMMON	 False
SQUAD	 True
Confuse	 True

Rust[edit]

This implementation uses a backtracking search.

use std::iter::repeat;

fn rec_can_make_word(index: usize, word: &str, blocks: &[&str], used: &mut[bool]) -> bool {
    let c = word.chars().nth(index).unwrap().to_uppercase().next().unwrap();
    for i in 0..blocks.len() {
        if !used[i] && blocks[i].chars().any(|s| s == c) {
            used[i] = true;
            if index == 0 || rec_can_make_word(index - 1, word, blocks, used) {
                return true;
            }
            used[i] = false;
        }
    }
    false
}

fn can_make_word(word: &str, blocks: &[&str]) -> bool {
    return rec_can_make_word(word.chars().count() - 1, word, blocks, 
                             &mut repeat(false).take(blocks.len()).collect::<Vec<_>>());
}

fn main() {
    let blocks = [("BO"), ("XK"), ("DQ"), ("CP"), ("NA"), ("GT"), ("RE"), ("TG"), ("QD"), ("FS"), 
                  ("JW"), ("HU"), ("VI"), ("AN"), ("OB"), ("ER"), ("FS"), ("LY"), ("PC"), ("ZM")];
    let words = ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"];
    for word in &words {
        println!("{} -> {}", word, can_make_word(word, &blocks))
    }
}
Output:
A -> true
BARK -> true
BOOK -> false
TREAT -> true
COMMON -> false
SQUAD -> true
CONFUSE -> true

Scala[edit]

Library: Scala
object AbcBlocks extends App {

  protected class Block(face1: Char, face2: Char) {

    def isFacedWith(that: Char) = { that == face1 || that == face2 }
    override def toString() = face1.toString + face2
  }
  protected object Block {
    def apply(faces: String) = new Block(faces.head, faces.last)
  }

  type word = Seq[Block]

  private val blocks = List(Block("BO"), Block("XK"), Block("DQ"), Block("CP"), Block("NA"),
    Block("GT"), Block("RE"), Block("TG"), Block("QD"), Block("FS"),
    Block("JW"), Block("HU"), Block("VI"), Block("AN"), Block("OB"),
    Block("ER"), Block("FS"), Block("LY"), Block("PC"), Block("ZM"))

  private def isMakeable(word: String, blocks: word) = {

    def getTheBlocks(word: String, blocks: word) = {

      def inner(word: String, toCompare: word, rest: word, accu: word): word = {
        if (word.isEmpty || rest.isEmpty || toCompare.isEmpty) accu
        else if (toCompare.head.isFacedWith(word.head)) {
          val restant = rest diff List(toCompare.head)
          inner(word.tail, restant, restant, accu :+ toCompare.head)
        } else inner(word, toCompare.tail, rest, accu)
      }
      inner(word, blocks, blocks, Nil)
    }

    word.lengthCompare(getTheBlocks(word, blocks).size) == 0
  }

  val words = List("A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSED", "ANBOCPDQERSFTGUVWXLZ")
  // Automatic tests
  assert(isMakeable(words(0), blocks))
  assert(isMakeable(words(1), blocks))
  assert(!isMakeable(words(2), blocks)) // BOOK not
  assert(isMakeable(words(3), blocks))
  assert(!isMakeable(words(4), blocks)) // COMMON not
  assert(isMakeable(words(5), blocks))
  assert(isMakeable(words(6), blocks))
  assert(isMakeable(words(7), blocks))

  //words(7).mkString.permutations.foreach(s => assert(isMakeable(s, blocks)))

  words.foreach(w => println(s"$w can${if (isMakeable(w, blocks)) " " else "not "}be made."))
}

Scheme[edit]

In R5RS:

(define *blocks*
  '((#\B #\O) (#\X #\K) (#\D #\Q) (#\C #\P) (#\N #\A)
    (#\G #\T) (#\R #\E) (#\T #\G) (#\Q #\D) (#\F #\S)
    (#\J #\W) (#\H #\U) (#\V #\I) (#\A #\N) (#\O #\B)
    (#\E #\R) (#\F #\S) (#\L #\Y) (#\P #\C) (#\Z #\M)))

(define (exists p? li)
  (and (not (null? li))
       (or (p? (car li))
           (exists p? (cdr li)))))

(define (remove-one x li)
  (cond
    ((null? li) '())
    ((equal? (car li) x) (cdr li))
    (else (cons (car li) (remove-one x (cdr li))))))

(define (can-make-list? li blocks)
  (or (null? li)
      (exists
       (lambda (block)
         (and
          (member (char-upcase (car li)) block)
          (can-make-list? (cdr li) (remove-one block blocks))))
       blocks)))

(define (can-make-word? word)
  (can-make-list? (string->list word) *blocks*))
 
 
(define *words*
  '("A" "Bark" "book" "TrEaT" "COMMON" "squaD" "CONFUSE"))
 
(for-each
 (lambda (word)
   (display (if (can-make-word? word)
                "   Can make word: "
                "Cannot make word: "))
   (display word)
   (newline))
 *words*)
Output:
   Can make word: A
   Can make word: Bark
Cannot make word: book
   Can make word: TrEaT
Cannot make word: COMMON
   Can make word: squaD
   Can make word: CONFUSE

Seed7[edit]

$ include "seed7_05.s7i";

const func boolean: canMakeWords (in array string: blocks, in string: word) is func
  result
    var boolean: okay is FALSE;
  local
    var integer: index is 1;
  begin
    if word = "" then
      okay := TRUE;
    elsif length(blocks) <> 0 then
      while index <= length(blocks) and not okay do
        if blocks[index][1] = word[1] or blocks[index][2] = word[1] then
          okay := canMakeWords(blocks[.. pred(index)] & blocks[succ(index) ..], word[2 ..]);
        end if;
        incr(index);
      end while;
    end if;
  end func;

const array string: blocks is [] ("BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
                                  "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM");

const func boolean: canMakeWords (in string: word) is
  return canMakeWords(blocks, upper(word));

const proc: main is func
  local
    var string: word is "";
  begin
    for word range [] ("", "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "Confuse") do
      writeln(word rpad 10 <& canMakeWords(word));
    end for;
  end func;
Output:
          TRUE
A         TRUE
BARK      TRUE
BOOK      FALSE
TREAT     TRUE
COMMON    FALSE
SQUAD     TRUE
Confuse   TRUE

SenseTalk[edit]

function CanMakeWord word

	put [
		("B", "O"),
		("X", "K"),
		("D", "Q"),
		("C", "P"),
		("N", "A"),
		("G", "T"),
		("R", "E"),
		("T", "G"),
		("Q", "D"),
		("F", "S"),
		("J", "W"),
		("H", "U"),
		("V", "I"),
		("A", "N"),
		("O", "B"),
		("E", "R"),
		("F", "S"),
		("L", "Y"),
		("P", "C"),
		("Z", "M")
	] into blocks
	
	repeat with each character letter of word
		put False into found
		repeat with each item block of blocks by reference
			if item 1 of block is letter ignoring case or item 2 of block is letter ignoring case
				delete block
				put True into found
				exit repeat
			end if
		end repeat
		if found is False
			return False
		end if
	end repeat
	return True
	
end CanMakeWord
repeat with each item word in [
	"A",
	"BARK",
	"BOOK",
	"TREAT",
	"COMMON",
	"SQUAD",
	"CONFUSE"
        ]
	put CanMakeWord(word)
end repeat

SequenceL[edit]

Recursive Search Version[edit]

import <Utilities/Conversion.sl>;
import <Utilities/Sequence.sl>;

main(args(2)) :=
	let
		result[i] := args[i] ++ ": " ++ boolToString(can_make_word(args[i], InitBlocks));
	in
		delimit(result, '\n');

InitBlocks :=  ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"];
			
can_make_word(word(1), blocks(2)) :=
	let
		choices[i] := i when some(blocks[i] = toUpper(head(word)));
		blocksAfterChoice[i] := blocks[(1 ... (choices[i] - 1)) ++ ((choices[i] + 1) ... size(blocks))];
	in
		true when size(word) = 0
	else
		false when size(choices) = 0
	else
		some(can_make_word(tail(word), blocksAfterChoice));
		
toUpper(letter(0)) :=
	let
		ascii := asciiToInt(letter);
	in
		letter when ascii >= 65 and ascii <= 90
	else
		intToAscii(ascii -  32);
Output:
cmd:> main.exe A BARK BOOK TREAT COMMON SQUAD CONFUSE
"A: true
BARK: true
BOOK: false
TREAT: true
COMMON: false
SQUAD: true
CONFUSE: true"

RegEx Version[edit]

import <Utilities/Conversion.sl>;
import <Utilities/Sequence.sl>;
import <RegEx/RegEx.sl>;

main(args(2)) :=
	let
		result[i] := args[i] ++ ": " ++ boolToString(can_make_word(args[i], InitBlocks));
	in
		delimit(result, '\n');

InitBlocks :=  "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";
			
can_make_word(word(1), blocks(1)) :=
	let
		regEx := "(\\a" ++ [toUpper(head(word))] ++ "|" ++ [toUpper(head(word))] ++ "\\a)";
		
		newBlocks := replaceFirst(blocks, regEx, "");
	in
		true when size(word) = 0
	else
		false when size(newBlocks) = size(blocks)
	else
		can_make_word(tail(word), newBlocks);

toUpper(letter(0)) :=
	let
		ascii := asciiToInt(letter);
	in
		letter when ascii >= 65 and ascii <= 90
	else
		intToAscii(ascii -  32);

Sidef[edit]

Translation of: Perl
func can_make_word(word, blocks) {

    blocks.map! { |b| b.uc.chars.sort.join }.freq!

    func(word, blocks) {
        var char = word.shift
        var candidates = blocks.keys.grep { |k| 0 <= k.index(char) }

        for candidate in candidates {
            blocks{candidate} <= 0 && next;
            local blocks{candidate} = (blocks{candidate} - 1);
            return true if (word.is_empty || __FUNC__(word, blocks));
        }

        return false;
    }(word.uc.chars, blocks)
}

Tests:

var b1 = %w(BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM)
var b2 = %w(US TZ AO QA)

var tests = [
    ["A", true, b1],
    ["BARK", true, b1],
    ["BOOK", false, b1],
    ["TREAT", true, b1],
    ["COMMON", false, b1],
    ["SQUAD", true, b1],
    ["CONFUSE", true, b1],
    ["auto", true, b2],
];

tests.each { |t|
    var bool = can_make_word(t[0], t[2]);
    say ("%7s -> %s" % (t[0], bool));
    assert(bool == t[1])
}
Output:
      A -> true
   BARK -> true
   BOOK -> false
  TREAT -> true
 COMMON -> false
  SQUAD -> true
CONFUSE -> true
   auto -> true

Simula[edit]

COMMENT ABC PROBLEM;
BEGIN

    CLASS BLOCK(CH1, CH2); CHARACTER CH1, CH2;
    BEGIN
        BOOLEAN USED;
    END;

    CLASS GAME(WORD, POSSIBLE); TEXT WORD; BOOLEAN POSSIBLE;;

    BOOLEAN PROCEDURE CANMAKEWORD(WORD); TEXT WORD;
    BEGIN
        INTEGER I, NUMBLOCKS;
        BOOLEAN ALLPOSSIBLE, FOUND;
        NUMBLOCKS&#