[FWP] Puzzle thread on clpmod

[Vicki Brown <vlb@cfcl.com>]

At 18:27 -0700 7/5/99, owner-fwp@technofile.org wrote:
> I am sure everyone here reads clp.moderated--look at the puzzle there.

Just in case some of you still don't read clp.mod (even though you now know
it's in both Usenet and mailing list form :-), here's the puzzle:

Newsgroups: comp.lang.perl.moderated
Subject: This Week's Puzzle Solution
Date: 4 Jul 1999 20:10:22 GMT

This week's Weekend Edition Sunday Puzzle With Will Shortz on
National Public Radio presents a problem of a class that can be
defined as "match a substring of exactly n characters from the
unordered set of discrete characters { c1, c2, ..., cn }".

Here's the puzzle:

   Take the 9-letter-word SUBDEACON (the name of a church official).
   The word contains the first 5 letters of the alphabet, ABCD and E
   consecutively inside it, although not in alphabetical order. This
   is a two-part challenge: first, can you think of a common 8-letter
   word that has ABCDE consecutively inside it, not necessarily in
   alphabetical order; second, can you think of a common 7-letter word
   with the same property? Both answers are uncapitalized words that
   are familiar to everyone.

   (C) 1999 Will Shortz

And here's my stab at a Perl 5 solution:

#!/usr/local/bin/perl -w
require 5.000;
my $words = '/usr/share/dict/web2';
open WORDS, "<$words" or die "Cannot open file $words: $!";
while (<WORDS>) {
    print if (m/^[a-z]{7,8}\n$/ and
              m/([a-e])(?!\1)
                ([a-e])(?!\1|\2)
                ([a-e])(?!\1|\2|\3)
                ([a-e])(?!\1|\2|\3|\4)
                 [a-e]/x);
}

Is there a better way (more succinct, more elegant, more efficient,
whatever) to match this class of pattern?

-- 
Jim Monty
monty@primenet.com
Tempe, Arizona USA
-- --
       |\      _,,,---,,_       Vicki Brown <vlb@cfcl.com>
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