#!perl -wl

use strict;

$_ = shift @ARGV || "CLEANSE";
our (%kw, %words);
my ($match, @matches);
my $future = {"" => ""};

sub sortword { return join("", sort pop=~/./g) }

sub dissect { my %h; map $h{$_}++, split(//,pop); return \%h }

sub scrub {
        # make sure a word isn't longer than our
        # kw or has chars kw doesn't
        my $w = shift @_;
        return 0 if length($w) > $kw{"len"};
        my $d = dissect($w);
        map {
                return 0 if
                        !defined($kw{"d"}->{$_}) ||
                        $kw{"d"}->{$_} < $d->{$_}
         } keys %$d;
        return 1;
}
sub process {
        # run one iteration through %words
        my ($cand, @match, %future) = @_;
        for my $w (keys %words) {
                for my $c (keys %$cand) {
                        my $len = length($cand->{$c}) + $words{$w};
                        next if $len > $kw{"len"};
                        my $nk = "$c:$w";
                        $future{$nk} = sortword($cand->{$c} . $w);
                        if ($len == $kw{"len"}) {
                                push @match, $nk
                                        if $future{$nk} eq $kw{"kw"};
                                delete $future{$nk};
                        }
                }
        }
        return (\@match, \%future);
}

%kw = (
        "word"  => $_
        ,"len"  => length($_)
        ,"kw"   => sortword($_)
        ,"d"  => dissect($_)
);

map { chomp; $words{$_} = length() if scrub($_); } <DATA>;

while (keys %$future) {
        ($match, $future) = process($future);
        push @matches, @$match;
}

print "anagrams for " . $kw{"word"} . ":";
map print, @matches;

__DATA__
SEE
SCALENE
CLAN
EEL
BOB
PIZZA
SCAN
MONKS
PERL
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