This is not perl, and not exactly the same problem, but people interested in this might have a look at Cactus Kev's Poker Hand Evaluator.

As for myself, I had some fun developing this solution:

use strict;
use warnings;

sub rank { $_[0] % 13 }
sub suit { int($_[0] / 13) }

sub evaluate1 {
  my @cards = @_;

  my @rank_count = (0) x 13;
  my @suit_count = (0) x 4;
  my $max_rank = 0;
  my $rank_sum = 0;

  for my $c (@cards) {
    my $r = rank($c);
    $rank_count[$r]++;
    $rank_sum += $r;
    $max_rank = $r if ($r > $max_rank);
    $suit_count[suit($c)]++;
  }

  my ($r1, $r2) = reverse sort @rank_count;
  my ($s1) = reverse sort @suit_count;

  my $is_straight = 0;
  if ($r1 == 1) {
    if (($rank_sum == $max_rank*5 - 10) ||
        ($max_rank == 12 && ($rank_sum == 12*4 - 6) && $rank_count[0])
       ) {
      $is_straight = 1;
    }
  }

  my $n = 2*$r1**3 + 2*$r2 + 53*$is_straight + 56*($s1 == 5);

  if    ($n >= 130) { "4 of a kind" }
  elsif ($n >= 113) { "straight flush" }
  elsif ($n >= 60)  { "flush" }
  elsif ($n >= 58)  { "full house" }
  elsif ($n >= 57)  { "straight" }
  elsif ($n >= 56)  { "3 of a kind" }
  elsif ($n >= 20)  { "2 pair" }
  elsif ($n >= 18)  { "1 pair" }
  else              { "high card" }
}
[download]