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Self-describing numbers: Difference between revisions

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Self-describing numbers (view source)

Revision as of 13:40, 28 August 2022

3,093 bytes added ,  1 year ago
m
syntax highlighting fixup automation
(→‎{{header|Picat}}: Split into subsections.)
m (syntax highlighting fixup automation)
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{{trans|Python}}
 
<langsyntaxhighlight lang="11l">F is_self_describing(n)
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)))</langsyntaxhighlight>
 
{{out}}
Line 43:
 
=={{header|360 Assembly}}==
<langsyntaxhighlight lang="360asm">* Self-describing numbers 26/04/2020
SELFDESC CSECT
USING SELFDESC,R13 base register
Line 106:
XDEC DS CL12 temp fo xdeco
REGEQU
END SELFDESC </langsyntaxhighlight>
{{out}}
<pre>
Line 116:
 
=={{header|Ada}}==
<langsyntaxhighlight Adalang="ada">with Ada.Text_IO; use Ada.Text_IO;
procedure SelfDesc is
subtype Desc_Int is Long_Integer range 0 .. 10**10-1;
Line 140:
end if;
end loop;
end SelfDesc;</langsyntaxhighlight>
{{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}}
<langsyntaxhighlight lang="algol68">BEGIN
 
# return TRUE if number is self describing, FALSE otherwise #
Line 196:
)
 
END</langsyntaxhighlight>
{{out}}
<pre>
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=={{header|AppleScript}}==
<langsyntaxhighlight lang="applescript">use AppleScript version "2.4"
use framework "Foundation"
use scripting additions
Line 400:
set my text item delimiters to dlm
s
end unlines</langsyntaxhighlight>
{{Out}}
<pre>1210 -> true
Line 413:
=={{header|Arturo}}==
 
<langsyntaxhighlight lang="rebol">selfDescribing?: function [x][
digs: digits x
loop.with:'i digs 'd [
Line 422:
]
 
print select 1..22000 => selfDescribing?</langsyntaxhighlight>
 
{{out}}
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=={{header|AutoHotkey}}==
Uses CountSubString: [[Count occurrences of a substring#AutoHotkey]]
<langsyntaxhighlight AutoHotkeylang="autohotkey">; The following directives and commands speed up execution:
#NoEnv
SetBatchlines -1
Line 452:
return false
return true
}</langsyntaxhighlight>
Output:
<pre>---------------------------
Line 469:
 
=={{header|AWK}}==
<langsyntaxhighlight AWKlang="awk"># syntax: GAWK -f SELF-DESCRIBING_NUMBERS.AWK
BEGIN {
for (n=1; n<=100000000; n++) {
Line 485:
}
return(1)
}</langsyntaxhighlight>
<p>output:</p>
<pre>
Line 496:
 
=={{header|BASIC}}==
<langsyntaxhighlight lang="qbasic">Dim x, r, b, c, n, m As Integer
Dim a, d As String
Dim v(10), w(10) As Integer
Line 519:
Print "End"
sleep
end</langsyntaxhighlight>
 
=={{header|BBC BASIC}}==
{{works with|BBC BASIC for Windows}}
<langsyntaxhighlight lang="bbcbasic"> FOR N = 1 TO 5E7
IF FNselfdescribing(N) PRINT N
NEXT
Line 538:
N% DIV=10
ENDWHILE
= O% = SUM(D%())</langsyntaxhighlight>
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.
 
<langsyntaxhighlight lang="befunge">>1+9:0>\#06#:p#-:#1_$v
?v6:%+55:\+1\<<<\0:::<
#>g1+\6p55+/:#^_001p\v
^_@#!`<<v\+g6g10*+55\<
>:*:*:*^>>:01g1+:01p`|
^_\#\:#+.#5\#5,#$:<-$<</langsyntaxhighlight>
 
{{out}}
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=={{header|C}}==
Using integers instead of strings.
<langsyntaxhighlight lang="c">#include <stdio.h>
 
inline int self_desc(unsigned long long xx)
Line 594:
return 0;
}</langsyntaxhighlight>output<syntaxhighlight lang="text">1210
2020
21200
3211000
42101000</langsyntaxhighlight>
 
===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).
<langsyntaxhighlight lang="c">#include <stdio.h>
#include <stdlib.h>
#include <string.h>
Line 695:
puts("");
}
}</langsyntaxhighlight>
 
Output for base 36
<syntaxhighlight lang="text">$ time ./selfdesc.exe 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ
1210
2020
Line 735:
real 0m0.094s
user 0m0.046s
sys 0m0.030s</langsyntaxhighlight>
 
=={{header|C++}}==
<langsyntaxhighlight lang="cpp">
#include <iostream>
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return 0;
}
</syntaxhighlight>
</lang>
{{out}}
<pre>
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Uses C++11. Build with
g++ -std=c++11 sdn.cpp
<langsyntaxhighlight lang="cpp">#include <algorithm>
#include <array>
#include <iostream>
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}
}
}</langsyntaxhighlight>
Output:
<pre>
Line 870:
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.
<langsyntaxhighlight lang="lisp">(defun to-ascii (str) (mapcar #'char-code (coerce str 'list)))
 
(defun to-digits (n)
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(digits (to-digits n) (cdr digits)))
((null digits) t)
(if (not (eql (car digits) (aref counts ipos))) (return nil)))))</langsyntaxhighlight>
 
Output:
<syntaxhighlight lang="text">(loop for i from 1 to 4000000 do (if (self-described-p i) (print i)))
 
1210
Line 898:
21200
3211000
NIL</langsyntaxhighlight>
 
=={{header|Crystal}}==
{{trans|Ruby}}
<langsyntaxhighlight lang="ruby">def self_describing?(n)
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:
t = Time.monotonic
600_000_000.times { |n| (puts "#{n} in #{(Time.monotonic - t).total_seconds} secs";\
t = Time.monotonic) if self_describing?(n) }</langsyntaxhighlight>
System: I7-6700HQ, 3.5 GHz, Linux Kernel 5.6.17, Crystal 0.35
Compil: $ crystal build selfdescribing.cr --release
Line 924:
 
{{trans|Wren and Go}}
<langsyntaxhighlight lang="ruby">def selfDesc(n)
ns = n.to_s
nc = ns.size
Line 973:
end
osecs = (Time.monotonic - start).total_seconds
print("\nTook #{osecs} secs overall")</langsyntaxhighlight>
 
System: I7-6700HQ, 3.5 GHz, Linux Kernel 5.6.17, Crystal 0.35
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=={{header|D}}==
===Functional Version===
<langsyntaxhighlight lang="d">import std.stdio, std.algorithm, std.range, std.conv, std.string;
 
bool isSelfDescribing(in long n) pure nothrow @safe {
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void main() {
4_000_000.iota.filter!isSelfDescribing.writeln;
}</langsyntaxhighlight>
{{out}}
<pre>[1210, 2020, 21200, 3211000]</pre>
 
===A Faster Version===
<langsyntaxhighlight lang="d">bool isSelfDescribing2(ulong n) nothrow @nogc {
if (n <= 0)
return false;
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if (i.isSelfDescribing2)
i.writeln;
}</langsyntaxhighlight>
{{out}}
<pre>1210
Line 1,063:
 
=={{header|Elixir}}==
<langsyntaxhighlight lang="elixir">defmodule Self_describing do
def number(n) do
digits = Integer.digits(n)
Line 1,073:
 
m = 3300000
Enum.filter(0..m, fn n -> Self_describing.number(n) end)</langsyntaxhighlight>
 
{{out}}
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=={{header|Erlang}}==
 
<langsyntaxhighlight lang="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>
</lang>
 
=={{header|Factor}}==
<langsyntaxhighlight lang="factor">USING: kernel math.parser prettyprint sequences ;
IN: rosetta-code.self-describing-numbers
 
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digits dup [ digit-count = ] with map-index [ t = ] all? ;
 
100,000,000 <iota> [ self-describing-number? ] filter .</langsyntaxhighlight>
{{out}}
<pre>
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=={{header|Forth}}==
 
<langsyntaxhighlight lang="forth">\ where unavailable.
: third ( A b c -- A b c A ) >r over r> swap ;
: (.) ( u -- c-addr u ) 0 <# #s #> ;
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(.) [char] 0 third third bounds ?do
count i c@ [char] 0 - <> if drop 2drop false unloop exit then
loop drop 2drop true ;</langsyntaxhighlight>
 
=={{header|FreeBASIC}}==
<langsyntaxhighlight lang="freebasic">' FB 1.05.0 Win64
 
Function selfDescribing (n As UInteger) As Boolean
Line 1,148:
Print
Print "Press any key to quit"
Sleep</langsyntaxhighlight>
 
{{out}}
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=={{header|Go}}==
===Original===
<langsyntaxhighlight lang="go">package main
 
import (
Line 1,187:
}
}
}</langsyntaxhighlight>
Output produced by above program:
<pre>
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===Optimized===
Uses the optimized loop from the Wren entry - 12 times faster than before.
<langsyntaxhighlight lang="go">package main
 
import (
Line 1,256:
osecs := time.Since(start).Seconds()
fmt.Printf("\nTook %.1f secs overall\n", osecs)
}</langsyntaxhighlight>
 
{{out}}
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=={{header|Haskell}}==
<langsyntaxhighlight Haskelllang="haskell">import Data.Char
 
count :: Int -> [Int] -> Int
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isSelfDescribing <$>
[1210, 2020, 21200, 3211000, 42101000, 521001000, 6210001000]
print $ filter isSelfDescribing [0 .. 4000000]</langsyntaxhighlight>
Output:
<pre>[True,True,True,True,True,True,True]
Line 1,296:
 
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).
<langsyntaxhighlight lang="haskell">import Control.Monad (forM_, replicateM)
import Data.Char (intToDigit)
 
Line 1,325:
. filter isSelfDescribing
. allBaseNNumsOfLength
<$> [1 .. 8]</langsyntaxhighlight>
{{Out}}
<pre>[1210,2020,21200,3211000,42101000]</pre>
Line 1,333:
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">
<lang Icon>
procedure count (test_item, str)
result := 0
Line 1,362:
every write (self_describing_numbers ()\4)
end
</syntaxhighlight>
</lang>
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:
<langsyntaxhighlight lang="unicon">
procedure is_self_describing (n)
ns := string (n) # convert to a string
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procedure self_describing_numbers ()
suspend is_self_describing(seq())
end</langsyntaxhighlight>
 
=={{header|J}}==
 
'''Solution''':<langsyntaxhighlight lang="j"> digits =: 10&#.^:_1
counts =: _1 + [: #/.~ i.@:# , ]
selfdesc =: = counts&.digits"0 NB. Note use of "under"</langsyntaxhighlight>
'''Example''':<langsyntaxhighlight lang="j"> selfdesc 2020 1210 21200 3211000 43101000 42101000
1 1 1 1 0 1</langsyntaxhighlight>
'''Extra credit''':<langsyntaxhighlight lang="j"> I.@:selfdesc i. 1e6
1210 2020 21200</langsyntaxhighlight>
'''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:
 
=={{header|Java}}==
<langsyntaxhighlight lang="java">public class SelfDescribingNumbers{
public static boolean isSelfDescribing(int a){
String s = Integer.toString(a);
Line 1,423:
}
}
}</langsyntaxhighlight>
 
=={{header|JavaScript}}==
{{works with|SpiderMonkey}}
 
<langsyntaxhighlight lang="javascript">function is_self_describing(n) {
var digits = Number(n).toString().split("").map(function(elem) {return Number(elem)});
var len = digits.length;
Line 1,455:
for (var i=1; i<=3300000; i++)
if (is_self_describing(i))
print(i);</langsyntaxhighlight>
 
outputs
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=={{header|jq}}==
{{works with|jq|1.4}}
<langsyntaxhighlight lang="jq"># If your jq includes all/2 then comment out the following definition,
# which is slightly less efficient:
def all(generator; condition):
reduce generator as $i (true; if . then $i | condition else . end);</langsyntaxhighlight>
<langsyntaxhighlight lang="jq">def selfie:
def count(value): reduce .[] as $i (0; if $i == value then . + 1 else . end);
def digits: tostring | explode | map(. - 48);
Line 1,477:
else . as $digits
| all ( range(0; length); . as $i | $digits | (.[$i] == count($i)) )
end;</langsyntaxhighlight>
'''The task:'''
<langsyntaxhighlight lang="jq">range(0; 100000001) | select(selfie)</langsyntaxhighlight>
{{out}}
<langsyntaxhighlight lang="sh">$ jq -n -f Self-describing_numbers.jq
1210
2020
21200
3211000
42101000</langsyntaxhighlight>
 
=={{header|Julia}}==
{{works with|Julia|0.6}}
 
<langsyntaxhighlight lang="julia">function selfie(x::Integer)
ds = reverse(digits(x))
if sum(ds) != length(ds) return false end
Line 1,504:
 
selfies(x) = for i in 1:x selfie(i) && println(i) end
@time selfies(4000000)</langsyntaxhighlight>
 
{{out}}
Line 1,514:
 
=={{header|K}}==
<langsyntaxhighlight lang="k"> sdn: {n~+/'n=/:!#n:0$'$x}'
sdn 1210 2020 2121 21200 3211000 42101000
1 1 0 1 1 1
 
&sdn@!:1e6
1210 2020 21200</langsyntaxhighlight>
 
=={{header|Kotlin}}==
<langsyntaxhighlight lang="scala">// version 1.0.6
 
fun selfDescribing(n: Int): Boolean {
Line 1,542:
for (i in 0..99999999) if (selfDescribing(i)) print("$i ")
println()
}</langsyntaxhighlight>
 
{{out}}
Line 1,551:
 
=={{header|Liberty BASIC}}==
<langsyntaxhighlight lang="lb">'adapted from BASIC solution
FOR x = 1 TO 5000000
a$ = TRIM$(STR$(x))
Line 1,569:
NEXT x
PRINT
PRINT "End"</langsyntaxhighlight>
 
=={{header|LiveCode}}==
<langsyntaxhighlight LiveCodelang="livecode">function selfDescNumber n
local tSelfD, tLen
put len(n) into tLen
Line 1,582:
end repeat
return tSelfD
end selfDescNumber</langsyntaxhighlight>
To list the self-describing numbers to 10 million<langsyntaxhighlight LiveCodelang="livecode">on mouseUp
repeat with n = 0 to 10000000
if selfDescNumber(n) then
Line 1,591:
combine selfNum using comma
put selfNum
end mouseUp</langsyntaxhighlight>
Output<syntaxhighlight lang LiveCode="livecode">1210,2020,21200,3211000</langsyntaxhighlight>
 
=={{header|Logo}}==
<langsyntaxhighlight lang="logo">TO XX
BT
MAKE "AA (ARRAY 10 0)
Line 1,620:
FOR [Z 0 9][SETITEM :Z :AA "0 SETITEM :Z :BB "0 ]]
PR [END]
END</langsyntaxhighlight>
 
=={{header|Lua}}==
<langsyntaxhighlight lang="lua">function Is_self_describing( n )
local s = tostring( n )
 
Line 1,643:
for i = 1, 999999999 do
print( Is_self_describing( i ) )
end</langsyntaxhighlight>
 
=={{header|Mathematica}}/{{header|Wolfram Language}}==
<langsyntaxhighlight Mathematicalang="mathematica">isSelfDescribing[n_Integer] := (RotateRight[DigitCount[n]] == PadRight[IntegerDigits[n], 10])</langsyntaxhighlight>
<pre>Select[Range[10^10 - 1], isSelfDescribing]
-> {1210,2020,21200,3211000,42101000,521001000,6210001000}</pre>
 
=={{header|MATLAB}} / {{header|Octave}}==
<langsyntaxhighlight Matlablang="matlab">function z = isSelfDescribing(n)
s = int2str(n)-'0'; % convert to vector of digits
y = hist(s,0:9);
z = all(y(1:length(s))==s);
end;</langsyntaxhighlight>
 
Test function:
 
<langsyntaxhighlight Matlablang="matlab">for k = 1:1e10,
if isSelfDescribing(k),
printf('%i\n',k);
end
end; </langsyntaxhighlight>
 
Output:
Line 1,672:
 
=={{header|MiniScript}}==
<langsyntaxhighlight MiniScriptlang="miniscript">numbers = [12, 1210, 1300, 2020, 21200, 5]
occurrences = function(test, values)
Line 1,697:
end if
end for
</syntaxhighlight>
</lang>
{{out}}
<pre>
Line 1,711:
{{trans|Pascal}}
{{works with|ADW Modula-2|any (Compile with the linker option ''Console Application'').}}
<langsyntaxhighlight lang="modula2">
MODULE SelfDescribingNumber;
 
Line 1,763:
WriteLn;
END SelfDescribingNumber.
</syntaxhighlight>
</lang>
{{out}}
<pre>
Line 1,778:
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.
 
<langsyntaxhighlight lang="nim">import algorithm, sequtils, std/monotimes, times
 
type Digit = 0..9
Line 1,804:
echo n, " in ", getMonoTime() - t0
 
echo "\nTotal time: ", getMonoTime() - t0</langsyntaxhighlight>
 
{{out}}
Line 1,817:
 
=={{header|ooRexx}}==
<syntaxhighlight lang="oorexx">
<lang ooRexx>
-- REXX program to check if a number (base 10) is self-describing.
parse arg x y .
Line 1,834:
say number "is a self describing number"
end
</syntaxhighlight>
</lang>
'''output''' when using the input of: <tt> 0 999999999 </tt>
<pre style="overflow:scroll">
Line 1,848:
=={{header|PARI/GP}}==
This is a finite set...
<langsyntaxhighlight lang="parigp">S=[1210, 2020, 21200, 3211000, 42101000, 521001000, 6210001000];
isself(n)=vecsearch(S,n)</langsyntaxhighlight>
 
=={{header|Pascal}}==
<langsyntaxhighlight lang="pascal">Program SelfDescribingNumber;
 
uses
Line 1,894:
writeln (' ', x);
writeln('Job done.');
end.</langsyntaxhighlight>
Output:
<pre>
Line 1,911:
 
The number is self-descriptive If the arrays are equal.
<langsyntaxhighlight lang="perl">sub is_selfdesc
{
local $_ = shift;
Line 1,922:
for (0 .. 100000, 3211000, 42101000) {
print "$_\n" if is_selfdesc($_);
}</langsyntaxhighlight>
Output:
<pre>1210
Line 1,932:
=={{header|Phix}}==
{{Trans|Ada}}
<!--<langsyntaxhighlight Phixlang="phix">(phixonline)-->
<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:
<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>
<!--</langsyntaxhighlight>-->
{{out}}
<pre>
Line 1,968:
{{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.
<!--<langsyntaxhighlight Phixlang="phix">(phixonline)-->
<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:
<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>
<!--</langsyntaxhighlight>-->
{{out}}
<pre>
Line 2,026:
Finishes in less than a tenth of a second
{{trans|Seed7}}
<!--<langsyntaxhighlight Phixlang="phix">(phixonline)-->
<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:
<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>
<!--</langsyntaxhighlight>-->
{{out}}
as above plus
Line 2,081:
Works with: PHP 5.
 
<langsyntaxhighlight PHPlang="php"><?php
 
function is_describing($number) {
Line 2,098:
}
 
?></langsyntaxhighlight>
 
Output:
Line 2,111:
 
===Loop based approach===
<langsyntaxhighlight Picatlang="picat">self_desc(Num,L) =>
L = [ I.to_integer() : I in Num.to_string()],
Len = L.len,
Line 2,123:
fail
end
end.</langsyntaxhighlight>
 
===Constraint model 1===
Check if a number N is a self-describing number
<langsyntaxhighlight Picatlang="picat">self_desc_cp(Num, Sequence) =>
N = length(Num.to_string()),
 
Line 2,139:
scalar_product({ I : I in 0..N-1}, Sequence, N),
 
solve([ffd,updown], Sequence).</langsyntaxhighlight>
 
===Constraint model 2===
Same idea as <code>self_desc_cp/2</code> but a different usage: generate all solutions of a specific length Len.
<langsyntaxhighlight Picatlang="picat">self_desc_cp_len(Len, Num) =>
 
Sequence = new_list(Len),
Line 2,160:
to_num(List, Base, Num) =>
Len = length(List),
Num #= sum([List[I]*Base**(Len-I) : I in 1..Len]).</langsyntaxhighlight>
 
===Testing===
Testing some numbers using <code>self_desc_cp/2</code>:
<langsyntaxhighlight Picatlang="picat">go =>
List = [1210, 2020, 21200, 3211000, 42101000,
123456,98,10,-121,0,1,
Line 2,171:
printf("%w: %w\n", N, cond(self_desc_cp(N,_S),"self desc", "not self desc"))
end,
nl.</langsyntaxhighlight>
 
{{out}}
Line 2,189:
===Generate all solutions of a specific length===
Using <code>self_desc_cp_len/3</code> to generates all solutions of length 1..13:
<langsyntaxhighlight Picatlang="picat">go2 =>
Len :: 1..13,
println(findall(Num, (indomain(Len), self_desc_cp_len(Len,Num)))),
nl.
</syntaxhighlight>
</lang>
 
{{out}}
Line 2,207:
 
Here is one way to model this magic sequence problem.
<langsyntaxhighlight Picatlang="picat">go3 ?=>
member(N, 4..1000),
magic_sequenceN,Seq),
Line 2,223:
sum(Sequence) #= N,
sum([I*Sequence[I+1] : I in 0..N-1]) #= N,
solve([ff,split], Sequence).</langsyntaxhighlight>
 
{{out}}
Line 2,267:
===Algorithmic approach===
Except for the self describing number 2020, these sequences can be found by the following "algorithmic" approach:
<langsyntaxhighlight Picatlang="picat">magic_sequence_alg(N, Sequence) =>
Sequence = new_list(N,0),
Sequence[1] := N - 4,
Sequence[2] := 2,
Sequence[3] := 1,
Sequence[N-3] := 1.</langsyntaxhighlight>
 
=={{header|PicoLisp}}==
<langsyntaxhighlight PicoLisplang="picolisp">(de selfDescribing (N)
(fully '((D I) (= D (cnt = N (circ I))))
(setq N (mapcar format (chop N)))
(range 0 (length N)) ) )</langsyntaxhighlight>
Output:
<pre>: (filter selfDescribing (range 1 4000000))
Line 2,286:
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">
<lang PowerShell>
function Test-SelfDescribing ([int]$Number)
{
Line 2,299:
$sum -eq $digits.Count
}
</syntaxhighlight>
</lang>
<syntaxhighlight lang="powershell">
<lang PowerShell>
Test-SelfDescribing -Number 2020
</syntaxhighlight>
</lang>
{{Out}}
<pre>
Line 2,308:
</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">
<lang PowerShell>
11,2020,21200,321100 | ForEach-Object {
[PSCustomObject]@{
Line 2,315:
}
} | Format-Table -AutoSize
</syntaxhighlight>
</lang>
{{Out}}
<pre>
Line 2,328:
=={{header|Prolog}}==
Works with SWI-Prolog and library clpfd written by <b>Markus Triska</b>.
<langsyntaxhighlight Prologlang="prolog">:- use_module(library(clpfd)).
 
self_describling :-
Line 2,434:
 
run(Var,[Other|RRest], [1, Var],[Other|RRest]):-
dif(Var,Other).</langsyntaxhighlight>
 
Output
Line 2,452:
 
=={{header|PureBasic}}==
<langsyntaxhighlight PureBasiclang="purebasic">Procedure isSelfDescribing(x.q)
;returns 1 if number is self-describing, otherwise it returns 0
Protected digitCount, digit, i, digitSum
Line 2,524:
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
CloseConsole()
EndIf</langsyntaxhighlight>
Sample output:
<pre>1210 is selfdescribing.
Line 2,579:
 
=={{header|Python}}==
<langsyntaxhighlight lang="python">>>> def isSelfDescribing(n):
s = str(n)
return all(s.count(str(i)) == int(ch) for i, ch in enumerate(s))
Line 2,586:
[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)]</langsyntaxhighlight>
===Generator===
From [http://leetm.mingpao.com/cfm/Forum3.cfm?CategoryID=1&TopicID=1545&TopicOrder=Desc&TopicPage=1 here].
<langsyntaxhighlight lang="python">def impl(d, c, m):
if m < 0: return
if d == c[:len(d)]: print d
Line 2,599:
def self(n): impl([], [0]*(n+1), n)
self(10)</langsyntaxhighlight>
Output:
<pre>[]
Line 2,612:
=={{header|Quackery}}==
 
<langsyntaxhighlight Quackerylang="quackery"> [ tuck over peek
1+ unrot poke ] is item++ ( n [ --> [ )
 
Line 2,633:
4000000 times
[ i^ self-desc if
[ i^ echo cr ] ]</langsyntaxhighlight>
 
{{out}}
Line 2,644:
 
=={{header|Racket}}==
<langsyntaxhighlight Racketlang="racket">#lang racket
(define (get-digits number (lst null))
(if (zero? number)
Line 2,657:
(and bool
(= (count (lambda (x) (= x i)) digits)
(list-ref digits i)))))))</langsyntaxhighlight>
 
Sadly, the implementation is too slow for the optional task, taking somewhere around 3 minutes to check all numbers below 100.000.000
Line 2,663:
=={{header|Raku}}==
(formerly Perl 6)
<syntaxhighlight lang="raku" perl6line>my @values = <1210 2020 21200 3211000
42101000 521001000 6210001000 27 115508>;
 
Line 2,683:
}
 
.say if .&sdn for ^9999999;</langsyntaxhighlight>
Output:
<pre>
Line 2,702:
 
=={{header|Red}}==
<langsyntaxhighlight Redlang="red">Red []
 
;;-------------------------------------
Line 2,732:
 
repeat i 4000000 [ if isSDN? to-string i [print i] ]
</syntaxhighlight>
</lang>
'''output'''
<pre>1210
Line 2,745:
&nbsp; and &nbsp; [http://oeis.org/A138480 OEIS A138480].
===digit by digit test===
<langsyntaxhighlight lang="rexx">/*REXX program determines if a number (in base 10) is a self─describing, */
/*────────────────────────────────────────────────────── self─descriptive, */
/*────────────────────────────────────────────────────── autobiographical, or a */
Line 2,770:
if substr(?,j,1)\==L-length(space(translate(?,,j-1),0)) then return 1
end /*j*/
return 0 /*faster if used inverted truth table. */</langsyntaxhighlight>
<pre>
╔══════════════════════════════════════════════════════════════════╗
Line 2,793:
===faster method===
(Uses table lookup.)
<langsyntaxhighlight lang="rexx">/*REXX program determines if a number (in base 10) is a self-describing number.*/
parse arg x y . /*obtain optional arguments from the CL*/
if x=='' | x=="," then exit /*Not specified? Then get out of Dodge*/
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say right(n,w) 'is a self-describing number.'
end /*n*/
/*stick a fork in it, we're all done. */</langsyntaxhighlight>
'''output''' &nbsp; is the same as the 1<sup>st</sup> REXX example.
 
Line 2,818:
 
(Results are instantaneous.)
<langsyntaxhighlight lang="rexx">/*REXX program determines if a number (in base 10) is a self-describing number.*/
parse arg x y . /*obtain optional arguments from the CL*/
if x=='' | x=="," then exit /*Not specified? Then get out of Dodge*/
Line 2,834:
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. */</langsyntaxhighlight>
'''output''' &nbsp; is the same as the 1<sup>st</sup> REXX example.
<br><br>
 
=={{header|Ring}}==
<langsyntaxhighlight lang="ring">
# Project : Self-describing numbers
 
Line 2,864:
end
return sum
</syntaxhighlight>
</lang>
Output:
<pre>
Line 2,875:
 
=={{header|Ruby}}==
<langsyntaxhighlight lang="ruby">def self_describing?(n)
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)}</langsyntaxhighlight>
outputs
<pre>1210
Line 2,888:
 
{{trans|Wren}}
<langsyntaxhighlight lang="ruby">def selfDesc(n)
ns = n.to_s
nc = ns.size
Line 2,937:
end
osecs = (Time.now - start)
print("\nTook #{osecs} secs overall")</langsyntaxhighlight>
 
System: I7-6700HQ, 3.5 GHz, Linux Kernel 5.6.17, Ruby 2.7.1
Line 2,979:
 
=={{header|Run BASIC}}==
<langsyntaxhighlight Runbasiclang="runbasic">for i = 0 to 50000000 step 10
a$ = str$(i)
for c = 1 TO len(a$)
Line 2,995:
next i
print "== End =="
end</langsyntaxhighlight>
 
=={{header|Rust}}==
<langsyntaxhighlight lang="rust">
fn is_self_desc(xx: u64) -> bool
{
Line 3,021:
}
}
</syntaxhighlight>
</lang>
 
=={{header|Scala}}==
===Functional Programming===
<langsyntaxhighlight Scalalang="scala">object SelfDescribingNumbers extends App {
def isSelfDescribing(a: Int): Boolean = {
val s = Integer.toString(a)
Line 3,038:
 
println("Successfully completed without errors.")
}</langsyntaxhighlight>
 
See it running in your browser by [https://scastie.scala-lang.org/vQv61PpoSLeWwyVipLUevQ Scastie (JVM)].
 
=={{header|Seed7}}==
<langsyntaxhighlight lang="seed">$ include "seed7_05.s7i";
 
const func boolean: selfDescr (in string: stri) is func
Line 3,108:
gen(number);
end for;
end func;</langsyntaxhighlight>
 
Output:
Line 3,131:
=={{header|Sidef}}==
{{trans|Raku}}
<langsyntaxhighlight lang="ruby">func sdn(Number n) {
var b = [0]*n.len
var a = n.digits.flip
Line 3,146:
 
say "\nSelf-descriptive numbers less than 1e5 (in base 10):"
^1e5 -> each { |i| say i if sdn(i) }</langsyntaxhighlight>
{{out}}
<pre>
Line 3,166:
 
'''Extra credit:''' this will generate all the self-describing numbers in bases 7 to 36:
<langsyntaxhighlight lang="ruby">for b in (7 .. 36) {
var n = ((b-4) * b**(b-1) + 2*(b**(b-2)) + b**(b-3) + b**3 -> base(b))
say "base #{'%2d' % b}: #{n}"
}</langsyntaxhighlight>
{{out}}
<pre>
Line 3,206:
=={{header|Swift}}==
 
<langsyntaxhighlight lang="swift">import Foundation
 
extension BinaryInteger {
Line 3,238:
}
 
dispatchMain()</langsyntaxhighlight>
 
{{out}}
Line 3,250:
 
=={{header|Tcl}}==
<langsyntaxhighlight lang="tcl">package require Tcl 8.5
proc isSelfDescribing num {
set digits [split $num ""]
Line 3,265:
for {set i 0} {$i < 100000000} {incr i} {
if {[isSelfDescribing $i]} {puts $i}
}</langsyntaxhighlight>
 
=={{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.
<langsyntaxhighlight lang="bash">selfdescribing() {
local n=$1
local count=()
Line 3,289:
printf "%d\t%s\n" $n no
fi
done</langsyntaxhighlight>
{{output}}
<pre>0 no
Line 3,304:
Takes a very, very long time to check 100M numbers that I have to terminate the script. But the function
works.
<syntaxhighlight lang="vb">
<lang vb>
Function IsSelfDescribing(n)
IsSelfDescribing = False
Line 3,344:
end_time = Now
WScript.StdOut.WriteLine "Elapse Time: " & DateDiff("s",start_time,end_time) & " seconds"
</syntaxhighlight>
</lang>
 
=={{header|Wren}}==
Heavily optimized to complete the search in a reasonable time for a scripting language.
<langsyntaxhighlight lang="ecmascript">var selfDesc = Fn.new { |n|
var ns = "%(n)"
var nc = ns.count
Line 3,397:
}
var osecs = ((System.clock - start) * 10).round / 10
System.print("\nTook %(osecs) secs overall")</langsyntaxhighlight>
 
{{out}}
Line 3,415:
 
=={{header|XPL0}}==
<langsyntaxhighlight XPL0lang="xpl0">code ChOut=8, IntOut=11;
 
func SelfDesc(N); \Returns 'true' if N is self-describing
Line 3,449:
int N;
for N:= 0 to 100_000_000-1 do
if SelfDesc(N) then [IntOut(0, N); ChOut(0, ^ )]</langsyntaxhighlight>
 
Output:
Line 3,458:
=={{header|Yabasic}}==
{{trans|BBC_BASIC}}
<langsyntaxhighlight Yabasiclang="yabasic">FOR N = 1 TO 5E7
IF FNselfdescribing(N) PRINT N
NEXT
Line 3,477:
FOR I = 0 TO 8 : L = L + D(I) : NEXT
RETURN O = L
END SUB</langsyntaxhighlight>
 
=={{header|zkl}}==
<langsyntaxhighlight lang="zkl">fcn isSelfDescribing(n){
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"
}</langsyntaxhighlight>
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).
<langsyntaxhighlight lang="zkl">//[1..0x4_000_000].filter(isSelfDescribing).println();
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();</langsyntaxhighlight>
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}}
Thundergnat
10,339

edits

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