use strict;
use List::Util qw(shuffle);

# construct a standard deck
my @card;
foreach my $suit (qw(H C S D)) {
    foreach my $value (2..10, qw(J Q K A)) {
        push @card, $value . $suit;
    }
}

# now shuffle us up a pile of cards, perhaps composed of any
# number of decks
my @pile;
my $n = 4;      # number of decks in shuffled pile
push @pile, @card for (1..$n);
@pile = shuffle @pile;

# i think i'll try to generalize the algorithm such that it organizes
# the pile into distinct groups that each have only one of each item.
# in this test case, it will organize the pile into the appropriate
# number of decks, each containing only one of each card.
my $group = [[]];
while (my $item = shift @pile) {
    # search the current groups and add if item not found
    my $found;
    foreach my $i (0..$#$group) {
        unless ( grep { $item eq $_ } @{$group->[$i]} ) {
            push @{$group->[$i]}, $item;
            $found = 1;
            last;
        }
    }
    # if not found, make a new group with that item in it
    push @$group, [$item] unless $found;
}

# now print the results to see our handiwork
foreach (0..$#$group) { print join(" ", @{$group->[$_]}), "\n\n" }
[download]

10S QH 9S 6D 4S 10H JD JS KS AD 9C 7C KH 6S 8S 4D 10D 5D 10C QC 7S 9D 
+7H QS KD 2D 6H JC 5H 3D 8H JH 2S 9H 5C AC 2H AS 3C 8C KC 4C 5S 7D 3H 
+QD 8D 3S 2C AH 4H 6C

9C JS KH KS 4D QH 10S 7S AD 4S QS QC 5D 5H 8S 6H JD KD 9S 10D 5C 10H 8
+H 10C AS JH 2D 7D 6S 3H KC 3C 9H AC 9D 3D 4C 2H QD AH 8C 2C 3S JC 2S 
+7H 4H 6D 7C 6C 8D 5S

10S 4S QS 6H 8S 7S KS 10C 7D KD 4D AD JH 9C 9S QH KH 3D 5D 9D 6S 3H QD
+ 5H 2H JC 8C 2D 2S JD 3C 3S 10H AH AS 6D 2C QC 8H 4C 7C 9H 10D 4H JS 
+AC KC 5C 8D 6C 5S 7H

QD 4S 7S JC JH AD 3H 8S QH 3D QS KS 4D 10C KD 9D 6H 3S QC 6S 6D 8C 10S
+ 8H 7C AS 2D 2S AH 7D JD 5C 9C KC 8D 9H 10H KH 3C 2H 4H 4C 5D JS 10D 
+2C 5S 9S AC 5H 7H 6C
[download]