Here is a cute trick that you might want to contemplate.

If you make each card a 4-"digit" octal number, then three cards form a "set" if and only if ($a|$b|$c) equals ($a^$b^$c). You can use octal strings or octal numbers. I use octal strings below: 

#!/usr/bin/perl -w
use strict;

my %Desc= qw(
    0001 One
    0002 Two
    0004 Three
    0010 Red
    0020 Blue
    0040 Green
    0100 Hollow
    0200 Striped
    0400 Solid
    1000 Diamond
    2000 Squiggle
    4000 Oval
);

my @deck;
for my $a ( 1,2,4 ) {
    for my $b ( 1,2,4 ) {
        for my $c ( 1,2,4 ) {
            for my $d ( 1,2,4 ) {
                push @deck, "$a$b$c$d";
            }
        }
    }
}

sub isSet {
    my( $a, $b, $c )= @_;
    return ($a|$b|$c) eq ($a^$b^$c);
}

sub showCard {
    my( $card )= @_;
    my @desc;
    for my $bit ( sort keys %Desc ) {
        if( $bit eq ( $bit & $card ) ) {
            push @desc, $Desc{$bit};
        }
    }
    return "@desc";
}

while( 1 ) {
    for my $n ( reverse @deck-2..@deck ) {
        my $r = rand $n;
        @deck[$n-1,$r]= @deck[$r,$n-1];
    }
    if( isSet( @deck[-3..-1] ) ) {
        print showCard( $_ ), $/
            for @deck[-3..-1];
        exit;
    }
}

[download]

Update: Replaced nested maps with clearer, shorter for()s.

- tye        

In reply to Re: Solver for the game "Set" matches three times (octal) by tye
in thread Solver for the game "Set" matches three times by skrapasor

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.