#!/usr/bin/perl -w
use strict;

use vars '@dict';
open(DICT, '</usr/dict/words') || die "/usr/dict/words: $!\n";
chomp(@dict = <DICT>);
close DICT;

sub match_crypto {
  my @pattern = split //, $_[0];
  my (@letters,%slots,@matches);
 WORDS:
  foreach my $word (@dict) {
    next unless length $word == @pattern;
    @letters = split //, $word;
    %slots = ();
    for (my $i = 0; $i < @letters; ++$i) {
      next WORDS if $letters[$i] eq $pattern[$i];
      if (exists $slots{$pattern[$i]}) {
        next WORDS unless $slots{$pattern[$i]} eq $letters[$i];
      }
      else {
        $slots{$pattern[$i]} = $letters[$i];
      }
    }
    push @matches, $word;
  }
  @matches;
}