[NBLUG/talk] I hate perl. :-)

[Chris Palmer]

William Tracy writes:

> Anyone who uses Perl for a program more than about fifty lines long
> needs to be slapped.

Ahh, but you can cram so much into those 50 lines!  ;)

Here is my version.  Apart from a few sanity checks (taint checking,
strict and warnings), an expanded command line syntax, and adherence to
my personal style rules, I also added a cache argument so that
duplicates are not printed.

The obvious performance improvement is to turn the recursion into
iteration.  This version is very slow.


#!/usr/bin/perl -T

use strict;
use warnings;

unless (@ARGV) {
    print STDERR "Usage: $0 word [...]";
    exit;
}

for my $wrd (@ARGV) {
    print "Anagrams of $wrd:\n";
    my %ngrms;
    anagrams('', $wrd, \%ngrms);
    print map { $_ . "\n" } sort keys %ngrms;
}

sub anagrams {
    my ($so_far, $remaining, $cache) = @_;

    if (length($remaining) > 0) {
        for (my $i = 0; $i < length($remaining); $i++) {
            anagrams($so_far . substr($remaining, $i, 1),
                     substr($remaining, 0, $i) . substr($remaining, $i + 1),
		     $cache);
        }
    } else {
        $cache->{$so_far} = defined;
    }
}


-- 
http://www.eff.org/about/staff/#chris_palmer

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