[rochester-pm-list] Jumble solver

[Bob Walton]

Shawn, the problem is in your sub superfind:  You modify the global
@words in it.  The modification mechanism is:  You iterate over @words
with $word being  a reference to each entry of @words in turn.  When you
modify $word, you modify @words, since $word is a reference to an
element of @words.  One fix is shown in your code below, involving just
assigning a temporary variable to hold $word during the modifications. 
The word "wet" is found with that modification.

Shawn Porter wrote:
> 
> I'm writing a little script to solve two word Jumbles and I'm having a
> strange problem that I can't track down.  Here is what I get when testing
> this script:
> 
> --
> % echo; ./jumble; echo; ./jumble 1
> 
> finding: twtowlee, 5
> found: towel
> 1: towel twe
> finding: twe, 3
> found: wet
> 2: wet
> towel wet
> 
> finding: noiiontwsep, 8
> found: opinions
> found: position
> 1: position nwe
> finding: nwe, 3
> found: new
> 2: new
> position new
> 1: opinions twe
> finding: twe, 3
> 
> --
> With the second set of letters it fails to find the word 'wet' when
> searching for a 3 letter word with the letters 'twe' but with the first
> set of letters it works fine.  I can't figure out the problem.  Any ideas?
> 
> The entire source is below... sorry for the complete lack of comments, I
> whipped this out in like 10 minutes then racked my brain for about 20
> trying to figure out this problem.... I'm stumped.
> 
> --
> Shawn Porter
> http://www.rit.net/sporter
> sporter at rit.net
> 
> --
> #!/usr/bin/perl
> if($ARGV[0] == 1)
> {
>   $letters = "noiiontwsep";
>   @groups = (3, 8);
> }
> else
> {
>   $letters = "twtowlee";
>   @groups = (3, 5);
> }
> 
> @groups = reverse sort(@groups);
> 
> open(WORDS, "/usr/dict/words");
> while(<WORDS>)
> {
>   chomp;
>   push(@words, $_);
> }
> close(WORDS);
> 
> my $hashref = superfind($letters, $groups[0]);
> my %found = %$hashref;
> 
> foreach my $word (keys %found)
> {
>   print "1: " . $word . " " . $found{$word} . "\n";
> 
>   my $hashref2 = superfind($found{$word}, $groups[1]);
>   my %found2 = %$hashref2;
> 
>   foreach my $secondword (keys %found2)
>   {
>     print "2: " . $secondword . "\n";
>     if($found{$secondword} eq '')
>     {
>       print $word . " " . $secondword . "\n";
>     }
>   }
> }
> 
> sub superfind
> {
>   my $letters = shift;
>   my $length = shift;
> 
>   print "finding: $letters, $length\n";
> 
>   my %found;
>   my @letters;
>   until($letters eq '')
>   {
>     push(@letters, chop($letters));
>   }
> 
>   foreach my $word (@words)
>   {
>     next unless(length($word) == $length);
> 
>     my $orig = $word;
	my $tword = $word;
>     my @used;
>     my @unused;
>     my @possible = @letters;
> 
>     while (@possible)
>     {
>       my $l = pop(@possible);
>       if($tword =~ /$l/)
>       {
>         $tword =~ s/$l//;
>         push(@used, $l);
>       }
>       else
>       {
>         push(@unused, $l);
>       }
>     }
> 
>     if(scalar(@used) == $length)
>     {
>       print "found: $orig\n";
>       my $unused;
>       foreach(@unused)
>       {
>         $unused .= $_;
>       }
>       $found{$orig} = $unused;
>     }
>   }
> 
>   return(\%found);
> }