Dear Monks
Anybody up for some golf?
I have been asked to find a number that is a permutation of
123456789 and has the following properties.
The complete number should be divisable by 9
The number built of the first 8 digits should be dividable by 8
The number built of the first 7 digits should be divisable by 7
and so forth until you just have one digit that is divisable by one
(the last part is pretty easy ;-)
I wrote a perl script to find the number(s) it is 157 characters long (no strict):
sub t{($n,@c)=@_;my@w;foreach$c(@c){for$u(1..9)
{next if$c=~/$u/;$y=$c.$u;if($y%$n==0){push(@w,$y)}}}return@w}
my@c=(1..9);for$i(2..9){@c=&t($i,@c)}print"@c\n"

[download]
Here is a bit more readable version of the same program (runs under strict):
use warnings;
use strict;

sub iter {
 my ($n, @old_cand) = @_;
 my @new_cand;
 foreach my $cand (@old_cand) {
  for my $num (1..9) {
   next if $cand =~ /$num/;
   my $new_c=$cand.$num;
   if ($new_c % $n == 0) {push ( @new_cand, $new_c)}
  }
 }
 return @new_cand;
}

my @c=(1..9);
for my $i (2..9) {
 @c=&iter($i, @c);
}
print "@c\n";

[download]
Comments?
si_lence

In reply to Golf the numbers! by si_lence

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.