Code Golf: Tic Tac Toe

Answer 1

I'm not happy with repeating myself (horizontal/vertical, and the diagonals), but I think it's a fair start.

C# w/LINQ:

public static int GetVictor(int[] b)
{
    var r = Enumerable.Range(0, 3);
    return r.Select(i => r.Aggregate(3, (s, j) => s & b[i * 3 + j])).Concat(
        r.Select(i => r.Aggregate(3, (s, j) => s & b[j * 3 + i]))).Aggregate(
        r.Aggregate(3, (s, i) => s & b[i * 3 + i]) | r.Aggregate(3, (s, i) => s & b[i * 3 + (2 - i)]),
        (s, i) => s | i);
}

Strategy: Bitwise AND each element of a row/column/diagonal with the other elements (with 3 as a seed) to obtain a victor for that subset, and OR them all together at the end.