[Shootout-list] External libraries and Fannkuch.pl

[Joel Hoffman]

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Attached is a Perl Fannkuch program (using the official algorithm as 
described) which uses Algorithm::FastPermute from CPAN. It is actually 
not particularly fast, but at least I think it is easy to read!

I read Brent Fulgham's post about external libraries, but it's not clear 
how repositories like CPAN are affected. It's really very normal (or at 
least it should be) to use random modules from CPAN in everyday Perl 
programming, but they aren't part of the core language. Some are pure 
Perl and some (like this one) are implemented in C. I haven't seen 
anything else using CPAN libraries, though, so is this acceptable?

Joel


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#!/usr/bin/perl
# The Great Computer Language Shootout
#   http://shootout.alioth.debian.org

#   contributed by Joel Hoffman
#   To run:   fannkuch.pl 9
#

use strict;
use Algorithm::FastPermute;

my $mx = 0;

my @array = (0..$ARGV[0]-1);

permute { 

   my @b = @array; 
   my $flips = 0; 

   while ((my $k = $b[0]) != 0) { 

      @b[0..$k] = reverse @b[0..$k]; 
      $flips++; 

   } 

   $mx = $flips if $flips > $mx; 

} @array;

print "Pfannkuchen($ARGV[0]) = $mx\n";

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