Self-describing numbers: Difference between revisions
m
→{{header|Wren}}: Changed to Wren S/H
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Line 31:
{{trans|Python}}
<
V s = String(n)
R all(enumerate(Array(s)).map((i, ch) -> @s.count(String(i)) == Int(ch)))
print((0.<4000000).filter(x -> is_self_describing(x)))</
{{out}}
Line 43:
=={{header|360 Assembly}}==
<
SELFDESC CSECT
USING SELFDESC,R13 base register
Line 106:
XDEC DS CL12 temp fo xdeco
REGEQU
END SELFDESC </
{{out}}
<pre>
Line 116:
=={{header|Ada}}==
<
procedure SelfDesc is
subtype Desc_Int is Long_Integer range 0 .. 10**10-1;
Line 140:
end if;
end loop;
end SelfDesc;</
{{out}}
<pre>1210
Line 151:
{{works with|ALGOL 68|Revision 1 - no extensions to language used}}
{{works with|ALGOL 68G|Any - tested with release 2.6.win32}}
<
# return TRUE if number is self describing, FALSE otherwise #
Line 196:
)
END</
{{out}}
<pre>
Line 207:
=={{header|AppleScript}}==
<
use framework "Foundation"
use scripting additions
Line 400:
set my text item delimiters to dlm
s
end unlines</
{{Out}}
<pre>1210 -> true
Line 413:
=={{header|Arturo}}==
<
digs: digits x
loop.with:'i digs 'd [
Line 422:
]
print select 1..22000 => selfDescribing?</
{{out}}
Line 430:
=={{header|AutoHotkey}}==
Uses CountSubString: [[Count occurrences of a substring#AutoHotkey]]
<
#NoEnv
SetBatchlines -1
Line 452:
return false
return true
}</
Output:
<pre>---------------------------
Line 469:
=={{header|AWK}}==
<
BEGIN {
for (n=1; n<=100000000; n++) {
Line 485:
}
return(1)
}</
<p>output:</p>
<pre>
Line 496:
=={{header|BASIC}}==
<
Dim a, d As String
Dim v(10), w(10) As Integer
Line 519:
Print "End"
sleep
end</
=={{header|BBC BASIC}}==
{{works with|BBC BASIC for Windows}}
<
IF FNselfdescribing(N) PRINT N
NEXT
Line 538:
N% DIV=10
ENDWHILE
= O% = SUM(D%())</
Output:
<pre>
Line 553:
Be aware, though, that even with a fast interpreter, it's going to be a very long time before you see the full set of results.
<
?v6:%+55:\+1\<<<\0:::<
#>g1+\6p55+/:#^_001p\v
^_@#!`<<v\+g6g10*+55\<
>:*:*:*^>>:01g1+:01p`|
^_\#\:#+.#5\#5,#$:<-$<</
{{out}}
Line 569:
=={{header|C}}==
Using integers instead of strings.
<
inline int self_desc(unsigned long long xx)
Line 594:
return 0;
}</
2020
21200
3211000
42101000</
===Backtracking version===
Backtracks on each digit from right to left, takes advantage of constraints "sum of digit values = number of digits" and "sum of (digit index * digit value) = number of digits". It is using as argument the list of allowed digits (example 012345789 to run the program in standard base 10).
<
#include <stdlib.h>
#include <string.h>
Line 695:
puts("");
}
}</
Output for base 36
<syntaxhighlight lang="text">$ time ./selfdesc.exe 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ
1210
2020
Line 735:
real 0m0.094s
user 0m0.046s
sys 0m0.030s</
=={{header|C++}}==
<
#include <iostream>
Line 812:
return 0;
}
</syntaxhighlight>
{{out}}
<pre>
Line 827:
Uses C++11. Build with
g++ -std=c++11 sdn.cpp
<
#include <array>
#include <iostream>
Line 852:
}
}
}</
Output:
<pre>
Line 863:
6210001000
</pre>
=={{header|CLU}}==
<syntaxhighlight lang="clu">self_describing = proc (n: int) returns (bool)
digits: array[int] := array[int]$predict(10, 10)
counts: array[int] := array[int]$fill(0, 10, 0)
while n > 0 do
digit: int := n // 10
n := n/10
array[int]$addl(digits, digit)
counts[digit] := counts[digit] + 1
end
array[int]$set_low(digits, 0)
for pos: int in array[int]$indexes(digits) do
if counts[pos] ~= digits[pos] then return(false) end
end
return(true)
end self_describing
start_up = proc ()
po: stream := stream$primary_output()
for n: int in int$from_to(1, 100000000) do
if self_describing(n) then
stream$putl(po, int$unparse(n))
end
end
end start_up</syntaxhighlight>
{{out}}
<pre>1210
2020
21200
3211000
42101000</pre>
=={{header|Common Lisp}}==
Line 870 ⟶ 905:
probably much faster because it wouldn't have to allocate an array and then
turn around and "interpret" it back out but I didn't really pursue it.
<
(defun to-digits (n)
Line 889 ⟶ 924:
(digits (to-digits n) (cdr digits)))
((null digits) t)
(if (not (eql (car digits) (aref counts ipos))) (return nil)))))</
Output:
<syntaxhighlight lang="text">(loop for i from 1 to 4000000 do (if (self-described-p i) (print i)))
1210
Line 898 ⟶ 933:
21200
3211000
NIL</
=={{header|Cowgol}}==
<syntaxhighlight lang="cowgol">include "cowgol.coh";
sub Length(n: uint32): (l: uint8) is
l := 0;
while n > 0 loop
n := n/10;
l := l+1;
end loop;
end sub;
sub IsSelfDescribing(n: uint32): (r: uint8) is
var positions: uint8[10];
var digitCounts: uint8[10];
MemSet(&positions[0], 0, @bytesof positions);
MemSet(&digitCounts[0], 0, @bytesof digitCounts);
var pos: uint8 := Length(n) - 1;
while n > 0 loop
var digit := (n % 10) as uint8;
positions[pos] := digit;
digitCounts[digit] := digitCounts[digit] + 1;
pos := pos - 1;
n := n / 10;
end loop;
r := 1;
pos := 0;
while pos < 10 loop
if positions[pos] != digitCounts[pos] then
r := 0;
break;
end if;
pos := pos + 1;
end loop;
end sub;
var n: uint32 := 1;
while n < 100000000 loop
if IsSelfDescribing(n) != 0 then
print_i32(n);
print_nl();
end if;
n := n + 1;
end loop;</syntaxhighlight>
{{out}}
<pre>1210
2020
21200
3211000
42101000</pre>
=={{header|Crystal}}==
{{trans|Ruby}}
<
digits = n.to_s.chars.map(&.to_i) # 12345 => [1, 2, 3, 4, 5]
digits.each_with_index.all? { |digit, idx| digits.count(idx) == digit }
Line 909 ⟶ 997:
t = Time.monotonic
600_000_000.times { |n| (puts "#{n} in #{(Time.monotonic - t).total_seconds} secs";\
t = Time.monotonic) if self_describing?(n) }</
System: I7-6700HQ, 3.5 GHz, Linux Kernel 5.6.17, Crystal 0.35
Compil: $ crystal build selfdescribing.cr --release
Line 924 ⟶ 1,012:
{{trans|Wren and Go}}
<
ns = n.to_s
nc = ns.size
Line 973 ⟶ 1,061:
end
osecs = (Time.monotonic - start).total_seconds
print("\nTook #{osecs} secs overall")</
System: I7-6700HQ, 3.5 GHz, Linux Kernel 5.6.17, Crystal 0.35
Line 990 ⟶ 1,078:
=={{header|D}}==
===Functional Version===
<
bool isSelfDescribing(in long n) pure nothrow @safe {
Line 999 ⟶ 1,087:
void main() {
4_000_000.iota.filter!isSelfDescribing.writeln;
}</
{{out}}
<pre>[1210, 2020, 21200, 3211000]</pre>
===A Faster Version===
<
if (n <= 0)
return false;
Line 1,046 ⟶ 1,134:
if (i.isSelfDescribing2)
i.writeln;
}</
{{out}}
<pre>1210
Line 1,061 ⟶ 1,149:
42101000
521001000</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
<syntaxhighlight lang="Delphi">
{This routine would normally be in a library. It is shown here for clarity.}
procedure GetDigitsRev(N: integer; var IA: TIntegerDynArray);
{Get an array of the integers in a number}
{Numbers returned from most to least significant}
var T,I,DC: integer;
begin
DC:=Trunc(Log10(N))+1;
SetLength(IA,DC);
for I:=DC-1 downto 0 do
begin
T:=N mod 10;
N:=N div 10;
IA[I]:=T;
end;
end;
function IsSelfDescribing(N: integer): boolean;
var IA: TIntegerDynArray;
var CA: array [0..9] of integer;
var I: integer;
begin
{Get digits, High-low order}
GetDigitsRev(N,IA);
for I:=0 to High(CA) do CA[I]:=0;
{Count number of each digit 0..9}
for I:=0 to High(IA) do
begin
CA[IA[I]]:=CA[IA[I]]+1;
end;
Result:=False;
{Compare original number with counts}
for I:=0 to High(IA) do
if IA[I]<>CA[I] then exit;
Result:=True;
end;
procedure SelfDescribingNumbers(Memo: TMemo);
var I: integer;
begin
for I:=0 to 100000000-1 do
if IsSelfDescribing(I) then
begin
Memo.Lines.Add(IntToStr(I));
end;
end;
</syntaxhighlight>
{{out}}
<pre>
1210
2020
21200
3211000
42101000
Elapsed Time: 23.584 Sec.
</pre>
=={{header|EasyLang}}==
Works with backtracking, iterative is too slow. Constraint: the sum of the digits count is the number of digits.
<syntaxhighlight lang="easylang">
proc test d[] . .
cnt[] = [ 0 0 0 0 0 0 0 0 0 0 ]
for d in d[]
cnt[d + 1] += 1
.
for i to len d[]
if cnt[i] <> d[i]
return
.
.
# found
for d in d[]
write d
.
print ""
.
proc backtr ind max . d[] .
if ind > len d[]
test d[]
return
.
for d = 0 to max
if d < 10
d[ind] = d
backtr ind + 1 max - d d[]
.
.
.
for i = 1 to 10
len d[] i
backtr 1 len d[] d[]
.
</syntaxhighlight>
{{out}}
<pre>
1210
2020
21200
3211000
42101000
521001000
6210001000
</pre>
=={{header|Elixir}}==
<
def number(n) do
digits = Integer.digits(n)
Line 1,073 ⟶ 1,279:
m = 3300000
Enum.filter(0..m, fn n -> Self_describing.number(n) end)</
{{out}}
Line 1,082 ⟶ 1,288:
=={{header|Erlang}}==
<
sdn(N) -> lists:map(fun(S)->length(lists:filter(fun(C)->C-$0==S end,N))+$0 end,lists:seq(0,length(N)-1))==N.
gen(M) -> lists:filter(fun(N)->sdn(integer_to_list(N)) end,lists:seq(0,M)).
</syntaxhighlight>
=={{header|Factor}}==
<
IN: rosetta-code.self-describing-numbers
Line 1,100 ⟶ 1,306:
digits dup [ digit-count = ] with map-index [ t = ] all? ;
100,000,000 <iota> [ self-describing-number? ] filter .</
{{out}}
<pre>
Line 1,108 ⟶ 1,314:
=={{header|Forth}}==
<
: third ( A b c -- A b c A ) >r over r> swap ;
: (.) ( u -- c-addr u ) 0 <# #s #> ;
Line 1,123 ⟶ 1,329:
(.) [char] 0 third third bounds ?do
count i c@ [char] 0 - <> if drop 2drop false unloop exit then
loop drop 2drop true ;</
=={{header|FreeBASIC}}==
<
Function selfDescribing (n As UInteger) As Boolean
Line 1,148 ⟶ 1,354:
Print
Print "Press any key to quit"
Sleep</
{{out}}
Line 1,158 ⟶ 1,364:
=={{header|Go}}==
===Original===
<
import (
Line 1,187 ⟶ 1,393:
}
}
}</
Output produced by above program:
<pre>
Line 1,201 ⟶ 1,407:
===Optimized===
Uses the optimized loop from the Wren entry - 12 times faster than before.
<
import (
Line 1,256 ⟶ 1,462:
osecs := time.Since(start).Seconds()
fmt.Printf("\nTook %.1f secs overall\n", osecs)
}</
{{out}}
Line 1,274 ⟶ 1,480:
=={{header|Haskell}}==
<
count :: Int -> [Int] -> Int
Line 1,290 ⟶ 1,496:
isSelfDescribing <$>
[1210, 2020, 21200, 3211000, 42101000, 521001000, 6210001000]
print $ filter isSelfDescribing [0 .. 4000000]</
Output:
<pre>[True,True,True,True,True,True,True]
Line 1,296 ⟶ 1,502:
Here are functions for generating all the self-describing numbers of a certain length. We capitalize on the fact (from Wikipedia) that a self-describing number of length n is a base-n number (i.e. all digits are 0..n-1).
<
import Data.Char (intToDigit)
Line 1,325 ⟶ 1,531:
. filter isSelfDescribing
. allBaseNNumsOfLength
<$> [1 .. 8]</
{{Out}}
<pre>[1210,2020,21200,3211000,42101000]</pre>
Line 1,333 ⟶ 1,539:
The following program contains the procedure <code>is_self_describing</code> to test if a number is a self-describing number, and the procedure <code>self_describing_numbers</code> to generate them.
<syntaxhighlight lang="icon">
procedure count (test_item, str)
result := 0
Line 1,362 ⟶ 1,568:
every write (self_describing_numbers ()\4)
end
</syntaxhighlight>
A slightly more concise solution can be derived from the above by taking
more advantage of Icon's (and Unicon's) automatic goal-directed
evaluation:
<
procedure is_self_describing (n)
ns := string (n) # convert to a string
Line 1,377 ⟶ 1,583:
procedure self_describing_numbers ()
suspend is_self_describing(seq())
end</
=={{header|J}}==
'''Solution''':<
counts =: _1 + [: #/.~ i.@:# , ]
selfdesc =: = counts&.digits"0 NB. Note use of "under"</
'''Example''':<
1 1 1 1 0 1</
'''Extra credit''':<
1210 2020 21200</
'''Discussion''': The use of <tt>&.</tt> here is a great example of its surprisingly broad applicability, and the elegance it can produce.
Line 1,397 ⟶ 1,603:
=={{header|Java}}==
<
public static boolean isSelfDescribing(int a){
String s = Integer.toString(a);
Line 1,423 ⟶ 1,629:
}
}
}</
=={{header|JavaScript}}==
{{works with|SpiderMonkey}}
<
var digits = Number(n).toString().split("").map(function(elem) {return Number(elem)});
var len = digits.length;
Line 1,455 ⟶ 1,661:
for (var i=1; i<=3300000; i++)
if (is_self_describing(i))
print(i);</
outputs
Line 1,465 ⟶ 1,671:
=={{header|jq}}==
{{works with|jq|1.4}}
<
# which is slightly less efficient:
def all(generator; condition):
reduce generator as $i (true; if . then $i | condition else . end);</
<
def count(value): reduce .[] as $i (0; if $i == value then . + 1 else . end);
def digits: tostring | explode | map(. - 48);
Line 1,477 ⟶ 1,683:
else . as $digits
| all ( range(0; length); . as $i | $digits | (.[$i] == count($i)) )
end;</
'''The task:'''
<
{{out}}
<
1210
2020
21200
3211000
42101000</
=={{header|Julia}}==
{{works with|Julia|0.6}}
<
ds = reverse(digits(x))
if sum(ds) != length(ds) return false end
Line 1,504 ⟶ 1,710:
selfies(x) = for i in 1:x selfie(i) && println(i) end
@time selfies(4000000)</
{{out}}
Line 1,514 ⟶ 1,720:
=={{header|K}}==
<
sdn 1210 2020 2121 21200 3211000 42101000
1 1 0 1 1 1
&sdn@!:1e6
1210 2020 21200</
=={{header|Kotlin}}==
<
fun selfDescribing(n: Int): Boolean {
Line 1,542 ⟶ 1,748:
for (i in 0..99999999) if (selfDescribing(i)) print("$i ")
println()
}</
{{out}}
Line 1,551 ⟶ 1,757:
=={{header|Liberty BASIC}}==
<
FOR x = 1 TO 5000000
a$ = TRIM$(STR$(x))
Line 1,569 ⟶ 1,775:
NEXT x
PRINT
PRINT "End"</
=={{header|LiveCode}}==
<
local tSelfD, tLen
put len(n) into tLen
Line 1,582 ⟶ 1,788:
end repeat
return tSelfD
end selfDescNumber</
To list the self-describing numbers to 10 million<
repeat with n = 0 to 10000000
if selfDescNumber(n) then
Line 1,591 ⟶ 1,797:
combine selfNum using comma
put selfNum
end mouseUp</
Output<syntaxhighlight lang
=={{header|Logo}}==
<
BT
MAKE "AA (ARRAY 10 0)
Line 1,620 ⟶ 1,826:
FOR [Z 0 9][SETITEM :Z :AA "0 SETITEM :Z :BB "0 ]]
PR [END]
END</
=={{header|Lua}}==
<
local s = tostring( n )
Line 1,643 ⟶ 1,849:
for i = 1, 999999999 do
print( Is_self_describing( i ) )
end</
=={{header|Mathematica}}/{{header|Wolfram Language}}==
<
<pre>Select[Range[10^10 - 1], isSelfDescribing]
-> {1210,2020,21200,3211000,42101000,521001000,6210001000}</pre>
=={{header|MATLAB}} / {{header|Octave}}==
<
s = int2str(n)-'0'; % convert to vector of digits
y = hist(s,0:9);
z = all(y(1:length(s))==s);
end;</
Test function:
<
if isSelfDescribing(k),
printf('%i\n',k);
end
end; </
Output:
Line 1,672 ⟶ 1,878:
=={{header|MiniScript}}==
<
occurrences = function(test, values)
Line 1,697 ⟶ 1,903:
end if
end for
</syntaxhighlight>
{{out}}
<pre>
Line 1,711 ⟶ 1,917:
{{trans|Pascal}}
{{works with|ADW Modula-2|any (Compile with the linker option ''Console Application'').}}
<
MODULE SelfDescribingNumber;
Line 1,763 ⟶ 1,969:
WriteLn;
END SelfDescribingNumber.
</syntaxhighlight>
{{out}}
<pre>
Line 1,778 ⟶ 1,984:
This is a brute-force algorithm. To speed-up, it uses integers instead of strings and the variable “digits” is allocated once, placed in global scope and accessed directly by the two functions (something I generally avoid). We have been able to check until 1_000_000_000.
<
type Digit = 0..9
Line 1,804 ⟶ 2,010:
echo n, " in ", getMonoTime() - t0
echo "\nTotal time: ", getMonoTime() - t0</
{{out}}
Line 1,817 ⟶ 2,023:
=={{header|ooRexx}}==
<syntaxhighlight lang="oorexx">
-- REXX program to check if a number (base 10) is self-describing.
parse arg x y .
Line 1,834 ⟶ 2,040:
say number "is a self describing number"
end
</syntaxhighlight>
'''output''' when using the input of: <tt> 0 999999999 </tt>
<pre style="overflow:scroll">
Line 1,848 ⟶ 2,054:
=={{header|PARI/GP}}==
This is a finite set...
<
isself(n)=vecsearch(S,n)</
=={{header|Pascal}}==
<
uses
Line 1,894 ⟶ 2,100:
writeln (' ', x);
writeln('Job done.');
end.</
Output:
<pre>
Line 1,911 ⟶ 2,117:
The number is self-descriptive If the arrays are equal.
<
{
local $_ = shift;
Line 1,922 ⟶ 2,128:
for (0 .. 100000, 3211000, 42101000) {
print "$_\n" if is_selfdesc($_);
}</
Output:
<pre>1210
Line 1,932 ⟶ 2,138:
=={{header|Phix}}==
{{Trans|Ada}}
<!--<
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">self_desc</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">)</span>
Line 1,955 ⟶ 2,161:
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"done (%s)\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">elapsed</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">time</span><span style="color: #0000FF;">()-</span><span style="color: #000000;">t0</span><span style="color: #0000FF;">)})</span>
<!--</
{{out}}
<pre>
Line 1,968 ⟶ 2,174:
{{trans|Python}}
Not quite as fast as I hoped it would be, although a bazillion times faster than the above and a good five times faster than Python, the following self(20) completes in just over a second whereas self(24) takes nearly 9s, and it continues getting exponentially slower after that. Curiously, it is the early stages (same output) that slow down, whereas the latter ones always complete fairly quickly.
<!--<
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">impl</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">d</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">m</span><span style="color: #0000FF;">)</span>
Line 2,001 ⟶ 2,207:
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #000000;">self</span><span style="color: #0000FF;">(</span><span style="color: #000000;">20</span><span style="color: #0000FF;">)</span>
<!--</
{{out}}
<pre>
Line 2,026 ⟶ 2,232:
Finishes in less than a tenth of a second
{{trans|Seed7}}
<!--<
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">constant</span> <span style="color: #004080;">string</span> <span style="color: #000000;">aleph</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">tagset</span><span style="color: #0000FF;">(</span><span style="color: #008000;">'9'</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'0'</span><span style="color: #0000FF;">)&</span><span style="color: #7060A8;">tagset</span><span style="color: #0000FF;">(</span><span style="color: #008000;">'z'</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'a'</span><span style="color: #0000FF;">)&</span><span style="color: #7060A8;">tagset</span><span style="color: #0000FF;">(</span><span style="color: #008000;">'Z'</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'A'</span><span style="color: #0000FF;">)</span>
Line 2,064 ⟶ 2,270:
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #0000FF;">?</span><span style="color: #7060A8;">elapsed</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">time</span><span style="color: #0000FF;">()-</span><span style="color: #000000;">t0</span><span style="color: #0000FF;">)</span>
<!--</
{{out}}
as above plus
Line 2,081 ⟶ 2,287:
Works with: PHP 5.
<
function is_describing($number) {
Line 2,098 ⟶ 2,304:
}
?></
Output:
Line 2,108 ⟶ 2,314:
=={{header|Picat}}==
Here are three approaches. The latter two use a constraint modelling approach (a variant to the classic '''magic sequence''' problem, see below).
===Loop based approach===
<syntaxhighlight lang="picat">self_desc(Num,L) =>
L = [ I.to_integer() : I in Num.to_string()],
Len = L.len,
Line 2,132 ⟶ 2,329:
fail
end
end.</syntaxhighlight>
===Constraint model 1===
Check if a number N is a self-describing number
<syntaxhighlight lang="picat">self_desc_cp(Num, Sequence) =>
N = length(Num.to_string()),
Line 2,150 ⟶ 2,345:
scalar_product({ I : I in 0..N-1}, Sequence, N),
solve([ffd,updown], Sequence).</syntaxhighlight>
===Constraint model 2===
Same idea as <code>self_desc_cp/2</code> but a different usage: generate all solutions of a specific length Len.
<syntaxhighlight lang="picat">self_desc_cp_len(Len, Num) =>
Sequence = new_list(Len),
Line 2,167 ⟶ 2,360:
solve([ffc,inout], Sequence).
%
Line 2,174 ⟶ 2,366:
to_num(List, Base, Num) =>
Len = length(List),
Num #= sum([List[I]*Base**(Len-I) : I in 1..Len]).</
===Testing===
Testing some numbers using <code>self_desc_cp/2</code>:
<syntaxhighlight lang="picat">go =>
List = [1210, 2020, 21200, 3211000, 42101000,
123456,98,10,-121,0,1,
Line 2,185 ⟶ 2,377:
printf("%w: %w\n", N, cond(self_desc_cp(N,_S),"self desc", "not self desc"))
end,
nl.</
{{out}}
Line 2,201 ⟶ 2,393:
</pre>
Using <code>self_desc_cp_len/3</code> to generates all solutions of length 1..13:
<syntaxhighlight lang="picat">go2 =>
Len :: 1..13,
println(findall(Num, (indomain(Len), self_desc_cp_len(Len,Num)))),
nl.
</syntaxhighlight>
{{out}}
<pre>[1210,2020,21200,3211000,42101000,521001000,6210001000,72100001000,821000001000,9210000001000]</pre>
===Magic sequence===
The two constraint modelling approaches are variations of the classic '''magic sequence''' problem:
''A magic sequence of length n is a sequence of integers x0 . . xn-1 between
Line 2,219 ⟶ 2,413:
Here is one way to model this magic sequence problem.
<
member(N, 4..1000),
magic_sequenceN,Seq),
Line 2,235 ⟶ 2,429:
sum(Sequence) #= N,
sum([I*Sequence[I+1] : I in 0..N-1]) #= N,
solve([ff,split], Sequence).</
{{out}}
Line 2,277 ⟶ 2,471:
...</pre>
===Algorithmic approach===
Except for the self describing number 2020, these sequences can be found by the following "algorithmic" approach:
<
Sequence = new_list(N,0),
Sequence[1] := N - 4,
Sequence[2] := 2,
Sequence[3] := 1,
Sequence[N-3] := 1.</
=={{header|PicoLisp}}==
<
(fully '((D I) (= D (cnt = N (circ I))))
(setq N (mapcar format (chop N)))
(range 0 (length N)) ) )</
Output:
<pre>: (filter selfDescribing (range 1 4000000))
Line 2,299 ⟶ 2,492:
According to the Wiki definition, the sum of the products of the index and the
digit contained at the index should equal the number of digits in the number:
<syntaxhighlight lang="powershell">
function Test-SelfDescribing ([int]$Number)
{
Line 2,312 ⟶ 2,505:
$sum -eq $digits.Count
}
</syntaxhighlight>
<syntaxhighlight lang="powershell">
Test-SelfDescribing -Number 2020
</syntaxhighlight>
{{Out}}
<pre>
Line 2,321 ⟶ 2,514:
</pre>
It takes a very long while to test 100,000,000 numbers, and since they are already known just test a few:
<syntaxhighlight lang="powershell">
11,2020,21200,321100 | ForEach-Object {
[PSCustomObject]@{
Line 2,328 ⟶ 2,521:
}
} | Format-Table -AutoSize
</syntaxhighlight>
{{Out}}
<pre>
Line 2,341 ⟶ 2,534:
=={{header|Prolog}}==
Works with SWI-Prolog and library clpfd written by <b>Markus Triska</b>.
<
self_describling :-
Line 2,447 ⟶ 2,640:
run(Var,[Other|RRest], [1, Var],[Other|RRest]):-
dif(Var,Other).</
Output
Line 2,465 ⟶ 2,658:
=={{header|PureBasic}}==
<
;returns 1 if number is self-describing, otherwise it returns 0
Protected digitCount, digit, i, digitSum
Line 2,537 ⟶ 2,730:
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
CloseConsole()
EndIf</
Sample output:
<pre>1210 is selfdescribing.
Line 2,592 ⟶ 2,785:
=={{header|Python}}==
<
s = str(n)
return all(s.count(str(i)) == int(ch) for i, ch in enumerate(s))
Line 2,599 ⟶ 2,792:
[1210, 2020, 21200, 3211000]
>>> [(x, isSelfDescribing(x)) for x in (1210, 2020, 21200, 3211000, 42101000, 521001000, 6210001000)]
[(1210, True), (2020, True), (21200, True), (3211000, True), (42101000, True), (521001000, True), (6210001000, True)]</
===Generator===
From [http://leetm.mingpao.com/cfm/Forum3.cfm?CategoryID=1&TopicID=1545&TopicOrder=Desc&TopicPage=1 here].
<
if m < 0: return
if d == c[:len(d)]: print d
Line 2,612 ⟶ 2,805:
def self(n): impl([], [0]*(n+1), n)
self(10)</
Output:
<pre>[]
Line 2,625 ⟶ 2,818:
=={{header|Quackery}}==
<
1+ unrot poke ] is item++ ( n [ --> [ )
Line 2,646 ⟶ 2,839:
4000000 times
[ i^ self-desc if
[ i^ echo cr ] ]</
{{out}}
Line 2,657 ⟶ 2,850:
=={{header|Racket}}==
<
(define (get-digits number (lst null))
(if (zero? number)
Line 2,670 ⟶ 2,863:
(and bool
(= (count (lambda (x) (= x i)) digits)
(list-ref digits i)))))))</
Sadly, the implementation is too slow for the optional task, taking somewhere around 3 minutes to check all numbers below 100.000.000
Line 2,676 ⟶ 2,869:
=={{header|Raku}}==
(formerly Perl 6)
<syntaxhighlight lang="raku"
42101000 521001000 6210001000 27 115508>;
Line 2,696 ⟶ 2,889:
}
.say if .&sdn for ^9999999;</
Output:
<pre>
Line 2,715 ⟶ 2,908:
=={{header|Red}}==
<
;;-------------------------------------
Line 2,745 ⟶ 2,938:
repeat i 4000000 [ if isSDN? to-string i [print i] ]
</syntaxhighlight>
'''output'''
<pre>1210
Line 2,758 ⟶ 2,951:
and [http://oeis.org/A138480 OEIS A138480].
===digit by digit test===
<
/*────────────────────────────────────────────────────── self─descriptive, */
/*────────────────────────────────────────────────────── autobiographical, or a */
Line 2,783 ⟶ 2,976:
if substr(?,j,1)\==L-length(space(translate(?,,j-1),0)) then return 1
end /*j*/
return 0 /*faster if used inverted truth table. */</
<pre>
╔══════════════════════════════════════════════════════════════════╗
Line 2,806 ⟶ 2,999:
===faster method===
(Uses table lookup.)
<
parse arg x y . /*obtain optional arguments from the CL*/
if x=='' | x=="," then exit /*Not specified? Then get out of Dodge*/
Line 2,824 ⟶ 3,017:
say right(n,w) 'is a self-describing number.'
end /*n*/
/*stick a fork in it, we're all done. */</
'''output''' is the same as the 1<sup>st</sup> REXX example.
Line 2,831 ⟶ 3,024:
(Results are instantaneous.)
<
parse arg x y . /*obtain optional arguments from the CL*/
if x=='' | x=="," then exit /*Not specified? Then get out of Dodge*/
Line 2,847 ⟶ 3,040:
if _<x | _>y then iterate /*if not self-describing, try again. */
say right(_, w) 'is a self-describing number.'
end /*n*/ /*stick a fork in it, we're all done. */</
'''output''' is the same as the 1<sup>st</sup> REXX example.
<br><br>
=={{header|Ring}}==
<
# Project : Self-describing numbers
Line 2,877 ⟶ 3,070:
end
return sum
</syntaxhighlight>
Output:
<pre>
Line 2,886 ⟶ 3,079:
42101000
</pre>
=={{header|RPL}}==
With some reasoning, one can find that digits must be between 0 and 4: just try manually to make a SDN with a 5 or greater and you will see it's impossible. The task enumerator takes this into account by counting in base 5, skipping numbers whose digital root is not equal to the number of digits and adding a final zero. Brute force is 30 times slower.
{{works with|HP|49}}
≪ STR→ { }
1 PICK3 SIZE '''FOR''' j
OVER j DUP SUB STR→ + '''NEXT'''
1 SF
0 ROT SIZE 1 - '''FOR''' j
DUP j 1 + GET
'''IF''' OVER 1 ≪ j == ≫ DOLIST ∑LIST ≠ '''THEN'''
1 CF DUP SIZE 'j' STO '''END'''
'''NEXT''' NIP
1 FS?
≫ '<span style="color:blue">SELF?</span>' STO
≪ →STR
1 OVER SIZE 1 - SUB <span style="color:grey">@ remove final zero</span>
0
1 PICK 3 SIZE '''FOR''' j
5 * OVER j DUP SUB STR→ + '''NEXT''' <span style="color:grey">@ convert from base 5</span>
NIP DUP
'''DO'''
DROP 1 + DUP ""
'''DO''' SWAP 5 IDIV2 ROT + <span style="color:grey">@ convert to base 5</span>
'''UNTIL''' OVER NOT '''END'''
NIP STR→
'''UNTIL''' DUP 1 - 9 MOD OVER XPON 1 + == '''END''' <span style="color:grey">@ check digital root</span>
NIP 10 * <span style="color:grey">@ add final zero</span>
≫ '<span style="color:blue">NEXTCAND</span>' STO
≪ → max
≪ { } 10
'''WHILE''' DUP max < '''REPEAT'''
'''IF''' DUP <span style="color:blue">SELF?</span> '''THEN''' SWAP OVER + SWAP '''END'''
<span style="color:blue">NEXTCAND</span>
'''END''' DROP
≫ ≫ '<span style="color:blue">TASK</span>' STO
9999 <span style="color:blue">TASK</span>
{{out}}
<pre>
1: {1210 2020}
</pre>
Runs in 43 seconds on a HP-48G.
=={{header|Ruby}}==
<
digits = n.digits.reverse
digits.each_with_index.all?{|digit, idx| digits.count(idx) == digit}
end
3_300_000.times {|n| puts n if self_describing?(n)}</
outputs
<pre>1210
Line 2,901 ⟶ 3,139:
{{trans|Wren}}
<
ns = n.to_s
nc = ns.size
Line 2,950 ⟶ 3,188:
end
osecs = (Time.now - start)
print("\nTook #{osecs} secs overall")</
System: I7-6700HQ, 3.5 GHz, Linux Kernel 5.6.17, Ruby 2.7.1
Line 2,992 ⟶ 3,230:
=={{header|Run BASIC}}==
<
a$ = str$(i)
for c = 1 TO len(a$)
Line 3,008 ⟶ 3,246:
next i
print "== End =="
end</
=={{header|Rust}}==
<
fn is_self_desc(xx: u64) -> bool
{
Line 3,034 ⟶ 3,272:
}
}
</syntaxhighlight>
=={{header|Scala}}==
===Functional Programming===
<
def isSelfDescribing(a: Int): Boolean = {
val s = Integer.toString(a)
Line 3,051 ⟶ 3,289:
println("Successfully completed without errors.")
}</
See it running in your browser by [https://scastie.scala-lang.org/vQv61PpoSLeWwyVipLUevQ Scastie (JVM)].
=={{header|Seed7}}==
<
const func boolean: selfDescr (in string: stri) is func
Line 3,121 ⟶ 3,359:
gen(number);
end for;
end func;</
Output:
Line 3,144 ⟶ 3,382:
=={{header|Sidef}}==
{{trans|Raku}}
<
var b = [0]*n.len
var a = n.digits.flip
Line 3,159 ⟶ 3,397:
say "\nSelf-descriptive numbers less than 1e5 (in base 10):"
^1e5 -> each { |i| say i if sdn(i) }</
{{out}}
<pre>
Line 3,179 ⟶ 3,417:
'''Extra credit:''' this will generate all the self-describing numbers in bases 7 to 36:
<
var n = ((b-4) * b**(b-1) + 2*(b**(b-2)) + b**(b-3) + b**3 -> base(b))
say "base #{'%2d' % b}: #{n}"
}</
{{out}}
<pre>
Line 3,219 ⟶ 3,457:
=={{header|Swift}}==
<
extension BinaryInteger {
Line 3,251 ⟶ 3,489:
}
dispatchMain()</
{{out}}
Line 3,263 ⟶ 3,501:
=={{header|Tcl}}==
<
proc isSelfDescribing num {
set digits [split $num ""]
Line 3,278 ⟶ 3,516:
for {set i 0} {$i < 100000000} {incr i} {
if {[isSelfDescribing $i]} {puts $i}
}</
=={{header|UNIX Shell}}==
{{works with|bash}}
Seeking self-describing numbers up to 100,000,000 is very time consuming, so we'll just verify a few numbers.
<
local n=$1
local count=()
Line 3,302 ⟶ 3,540:
printf "%d\t%s\n" $n no
fi
done</
{{output}}
<pre>0 no
Line 3,317 ⟶ 3,555:
Takes a very, very long time to check 100M numbers that I have to terminate the script. But the function
works.
<syntaxhighlight lang="vb">
Function IsSelfDescribing(n)
IsSelfDescribing = False
Line 3,357 ⟶ 3,595:
end_time = Now
WScript.StdOut.WriteLine "Elapse Time: " & DateDiff("s",start_time,end_time) & " seconds"
</syntaxhighlight>
=={{header|Wren}}==
Heavily optimized to complete the search in a reasonable time for a scripting language.
<
var ns = "%(n)"
var nc = ns.count
Line 3,410 ⟶ 3,648:
}
var osecs = ((System.clock - start) * 10).round / 10
System.print("\nTook %(osecs) secs overall")</
{{out}}
Line 3,428 ⟶ 3,666:
=={{header|XPL0}}==
<
func SelfDesc(N); \Returns 'true' if N is self-describing
Line 3,462 ⟶ 3,700:
int N;
for N:= 0 to 100_000_000-1 do
if SelfDesc(N) then [IntOut(0, N); ChOut(0, ^ )]</
Output:
Line 3,471 ⟶ 3,709:
=={{header|Yabasic}}==
{{trans|BBC_BASIC}}
<
IF FNselfdescribing(N) PRINT N
NEXT
Line 3,490 ⟶ 3,728:
FOR I = 0 TO 8 : L = L + D(I) : NEXT
RETURN O = L
END SUB</
=={{header|Zig}}==
{{works with|Zig|0.11.0dev}}
<syntaxhighlight lang="zig">const std = @import("std");</syntaxhighlight>
<syntaxhighlight lang="zig">// Return true if number is self describing
fn isSelfDescribing(number: u32) bool {
var n = number; // Zig parameters are immutable, copy to var.
// 10 is the maximum number of decimal digits in a 32-bit integer.
var array: [10]u32 = undefined;
// Add digits to array.
var i: u32 = 0;
while (n != 0 or i == 0) : (n /= 10) {
array[i] = n % 10;
i += 1;
}
var digits = array[0..i]; // Slice to give just the digits added.
std.mem.reverse(u32, digits);
// Check digits. Brute force.
for (digits, 0..) |predicted_count, predicted_digit| {
var count: u8 = 0;
for (digits) |digit| {
if (digit == predicted_digit) count += 1;
}
if (count != predicted_count) return false;
}
return true;
}</syntaxhighlight>
<syntaxhighlight lang="zig">pub fn main() anyerror!void {
const stdout = std.io.getStdOut().writer();
for (0..100_000_000) |number| {
if (isSelfDescribing(@intCast(number)))
try stdout.print("{}\n", .{number});
}
}</syntaxhighlight>
{{out}}
<pre>1210
2020
21200
3211000
42101000</pre>
===Alternative With "Optimizations"===
Here is an alternative implementation of <em>isSelfDescribing()</em> that
illustrates additional computationally cheap ways of partially eliminating
integers that are not self describing. These ideas were filched from other
solutions on this page (primarily Wren & PowerShell). The code works.
Refactoring for speed is a further exercise.
<syntaxhighlight lang="zig">/// Return true if number is self describing
fn isSelfDescribing(number: u32) bool {
// Get the digits (limit scope of variables in a Zig block expression)
// 1234 -> { 1, 2, 3, 4}
const digits = blk: {
var n = number; // Zig parameters are immutable, copy to var.
// 10 is the maximum number of decimal digits in a 32-bit integer.
var array: [10]u32 = undefined;
// Add base 10 digits to array.
var i: u32 = 0;
while (n != 0 or i == 0) : (n /= 10) {
array[i] = n % 10;
i += 1;
}
var slice = array[0..i]; // Slice to give only the digits added.
std.mem.reverse(u32, slice);
break :blk slice;
};
{
// wikipedia: last digit must be zero
if (digits[digits.len - 1] != 0) return false;
}
{
// cannot have a digit >= number of digits
for (digits) |n| if (n >= digits.len) return false;
}
{
// sum of digits must equal number of digits
var sum: u32 = 0;
for (digits) |n| sum += n; // > digits.len short-circuit ?
if (sum != digits.len) return false;
}
{
// sum of the products of the index and the digit contained at the index
// should equal the number of digits in the number
var sum: u32 = 0;
for (digits, 0..) |n, index| sum += n * @as(u32, @truncate(index));
if (sum != digits.len) return false;
}
// Final elimination. 100% effective. Brute force.
{
// Self describing check of digits.
for (digits, 0..) |expected_count, expected_digit| {
var count: u8 = 0;
for (digits) |digit| {
if (digit == expected_digit) count += 1;
}
if (count != expected_count) return false;
}
}
return true;
}</syntaxhighlight>
=={{header|zkl}}==
<
if (n.bitAnd(1)) return(False); // Wikipedia: last digit must be zero
nu:= n.toString();
ns:=["0".."9"].pump(String,nu.inCommon,"len"); //"12233".inCommon("2")-->"22"
(nu+"0000000000")[0,10] == ns; //"2020","2020000000"
}</
Since testing a humongous number of numbers is slow, chunk the task into a bunch of threads. Even so, it pegged my 8 way Ivy Bridge Linux box for quite some time (eg the Python & AWK solutions crush this one).
<
const N=0d500_000;
[1..0d100_000_000, N] // chunk and thread, 200 in this case
.apply(fcn(n){ n.filter(N,isSelfDescribing) }.future)
.filter().apply("noop").println();</
A future is a thread returning a [delayed] result, future.filter/future.noop will block until the future coughs up the result. Since the results are really sparse for the bigger numbers, filter out the empty results.
{{out}}
|