Google Code Jam 2013 - Qualification Round - Problem A. Tic-Tac-Toe-Tomek

tic.pl

use 5.012;
use warnings;

<>;
$/ = '';
my $c;
while (<>) {
    print 'Case #' . ++$c . ': ';
    s/\s+/ /g;
    if (/[OT]{4}|[OT](?:...[OT]){3}|[OT](?:....[OT]){3}|[OT](?:.....[OT]){3}/) {
        say 'O won';
    } elsif (/[XT]{4}|[XT](?:...[XT]){3}|[XT](?:....[XT]){3}|[XT](?:.....[XT]){3}/) {
        say 'X won';
    } elsif (/\./) {
        say 'Game has not completed';
    } else {
        say 'Draw';
    }
}