Okay, here's my take.

• my board is some kind of a 2D array.
• 'x' are 1.
• 'o' are -1.
• empty is 0.

we look for an absolute 3. But I'm sure there is a more mathematical way for this:

my @board;
while (<DATA>) {
        chomp;
        push @board, [split / /];
}

for my $i (0 .. 2) {
        my ($t1, $t2, $t3, $t4) = (0,0,0,0);
        for my $j ( 0 .. 2 ) {
                $t1 += $board[$i][$j];
                $t2 += $board[$j][$i];
                $t3 += $board[$j][$j];
                $t4 += $board[2 - $j][$j];
        }
    
        if (abs($t1) == 3 || abs($t2) == 3 
                || abs($t3) == 3 || abs($t4) == 3) {
                print "Win.\n";
                last;
        }
}


__DATA__
1 0 1
-1 1 -1
1 0 1
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