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ch-2.pl
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/
ch-2.pl
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#!/usr/bin/env perl
use strict;
use warnings;
use experimental qw{ say postderef signatures state };
use Algorithm::Permute;
use List::Util qw{ first uniq };
my @examples = (qw{ CAT GOOGLE SECRET });
for my $example (@examples) {
my $output = dictionary_rank($example);
say <<"END";
Input: \$word = '$example'
Output: $output
END
}
sub dictionary_rank ($word) {
my @word = split //, $word;
my @list;
my $iter = Algorithm::Permute->new( \@word );
while ( my @p = $iter->next ) {
push @list, join '', @p;
}
@list = uniq sort @list;
# would normally worry about a not-there response, but
# since the permutations are based on the word, the word
# has to be in there.
my $i = first { $word eq $list[$_] } 0 .. scalar @list;
return $i + 1;
}