#!/usr/bin/perl
use strict;

# NPR puzzler helper, 11/23/2003
# Find a pair of words, [X]rn and [X]m, which are antonyms.
# We can pull all such pairs from /usr/share/dict/words.

open(FH,"/usr/share/dict/words");

my @big_arr;
# grep through it the slow way
while (<FH>) {
	if (/([a-zA-Z]*rn$)/) {
		push @big_arr, $1;
	}
}

#print @big_arr;
close FH;

# there's got to be a better way to do this.
my @solutions;
#print "|all_words| = ".$#all_words."\n";
my $curr_word;
foreach (@big_arr) {
	$curr_word = substr($_,0,-2)."m";
	my $cmd = 'grep ^'.$curr_word.'$ /usr/share/dict/words';
	my $result = `$cmd`;
	if ($result) { 
		push @solutions, "$_ / $curr_word\n";
	}
}
close FH;

print @solutions;

##</code><code>##

#!/usr/bin/perl
use strict;

# NPR puzzler helper, 11/23/2003
# rewritten 12/15/2003 around 4 am.
# Find a pair of words, [X]rn and [X]m, which are antonyms.
# We can pull all such pairs from /usr/share/dict/words.

open(FH,"/usr/share/dict/words");

my (@rn_words, @solutions);

@rn_words = grep /([a-zA-Z]*rn$)/, <FH>;
chomp(@rn_words);

seek FH,0,0;

my $ptr = 0;
my $this = substr($rn_words[$ptr],0,-2).'m';
LOOP: while (<FH>) {
	chomp;
	next LOOP if ($_ lt $this);
	if ($_ eq $this)
		{ push @solutions, "$rn_words[$ptr] / $_\n"; }
	$ptr++;
	$this = substr($rn_words[$ptr],0,-2).'m';
	last unless defined $rn_words[$ptr];
}
close FH;

print @solutions;