Sorting algorithms/Permutation sort: Difference between revisions

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(Added Julia language)
m (→‎{{header|REXX}}: added/changed comments and whitespace, brought a function in-line, aligned some statements, used template for output.)
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call show 'before sort' /*show the before array elements. */
call show 'before sort' /*show the before array elements. */
say copies('░', 75) /*show separator line between displays.*/
say copies('░', 75) /*show separator line between displays.*/
call psets L /*generate items (!) permutations. */
call pSort L /*invoke the permutation sort. */
⚫
call pSort L /*invoke the permutation sort. */
call show ' after sort' /*show the after array elements. */
call show ' after sort' /*show the after array elements. */
say; say 'Permutation sort took' ? "permutations to find the sorted list."
say; say 'Permutation sort took ' ? " permutations to find the sorted list."
exit /*stick a fork in it, we're all done. */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
.pAdd: #=#+1; do j=1 for N; #.#=#.# !.j; end; return
.pAdd: #=#+1; do j=1 for N; #.#=#.# !.j; end; return /*add a permutation.*/
show: do j=1 for L; say ele right(j,wL) arg(1)":" translate(@.j,,'_'); end; return
show: do j=1 for L; say @e right(j,wL) arg(1)":" translate(@.j,,'_'); end; return
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
gen: @.=; @.1 = '---Four_horsemen_of_the_Apocalypse---'
gen: @.=; @.1 = '---Four_horsemen_of_the_Apocalypse---'
@.2 = '====================================='
@.2 = '====================================='
@.3 = 'Famine───black_horse'
@.3 = 'Famine───black_horse'
@.4 = 'Death───pale_horse'
@.4 = 'Death───pale_horse'
@.5 = 'Pestilence_[Slaughter]───red_horse'
@.5 = 'Pestilence_[Slaughter]───red_horse'
@.6 = 'Conquest_[War]───white_horse'
@.6 = 'Conquest_[War]───white_horse'
ele=right('element', 15) /*literal used for the display.*/
@e=right('element', 15) /*literal used for the display.*/
do L=1 while @.L\==''; @@.L=@.L; end; L=L-1; wL=length(L); return
do L=1 while @.L\==''; @@.L=@.L; end; L=L-1; wL=length(L); return
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
isOK: parse arg q /*see if Q list is in order. */
isOrd: parse arg q /*see if Q list is in order. */
_=word(q, 1); do j=2 to words(q); x=word(q, j); if x<_ then return 0
_=word(q, 1); do j=2 to words(q); x=word(q, j); if x<_ then return 0; _=x
_=x /*Out of order? [↑] ¬ sorted*/
end /*j*/ /* [↑] Out of order? ¬sorted*/
end /*j*/
do k=1 for #; _=word(#.?, k); @.k=@@._; end /*k*/; return 1 /*in order.*/
do k=1 for #; _=word(#.?, k); @.k=@@._; end /*k*/
return 1 /*they're all in order finally.*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
.pNext: procedure expose !.; parse arg n,i; nm=n-1
.pNext: procedure expose !.; parse arg n,i; nm=n-1
do k=nm by -1 for nm; kp=k+1
do k=nm by -1 for nm; kp=k+1
if !.k<!.kp then do; i=k; leave; end
if !.k<!.kp then do; i=k; leave; end
end /*k*/ /* [↓] swap two array elements*/
end /*k*/ /* [↓] swap two array elements*/
do j=i+1 while j<n; parse value !.j !.n with !.n !.j; n=n-1; end
do j=i+1 while j<n; parse value !.j !.n with !.n !.j; n=n-1; end /*j*/
if i==0 then return 0; do j=i+1 while !.j<!.i; end /*j*/
if i==0 then return 0 /*0: indicates no more perms. */
parse value !.j !.i with !.i !.j
do j=i+1 while !.j<!.i; end /*j*/ /*search perm for a lower value*/
parse value !.j !.i with !.i !.j /*swap two values in !. array.*/
return 1
return 1
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
psets: procedure expose !. # #.; parse arg n,#.; #=0; do f=1 for n; !.f=f; end /*f*/
pSort: parse arg n,#.; #=0 /*generate L items (!) permutations.*/
call .pAdd; do while .pNext(n,0); call .pAdd; end /*while*/
do f=1 for n; !.f=f; end /*f*/
call .pAdd; do while .pNext(n, 0); call .pAdd; end /*while*/
return #
⚫
do ?=1 until isOrd($); $= /*find perm.*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
pSort: do ?=1 until isOK($); $= /*find sorted permutation.*/
do m=1 for #; _=word(#.?, m); $=$ @._; end /*m*/ /*build list*/
do m=1 for #; _=word(#.? ,m); $=$ @._; end /*m*/
end /*?*/
end /*?*/
return</lang>
return</lang>
'''output''' &nbsp; using the default (internal) inputs:
{{out|output|text=&nbsp; when using the default (internal) inputs:}}
<pre>
<pre>
element 1 before sort: ---Four horsemen of the Apocalypse---
element 1 before sort: ---Four horsemen of the Apocalypse---
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element 6 after sort: Pestilence [Slaughter]───red horse
element 6 after sort: Pestilence [Slaughter]───red horse


Permutation sort took 21 permutations to find the sorted list.
Permutation sort took 21 permutations to find the sorted list.
</pre>
</pre>


Retrieved from "https://rosettacode.org/wiki/Sorting_algorithms/Permutation_sort"