X-O win

enum Player{
X,
O,
None
}

/*
0 | 1 | 2
----------
3 | 4 | 5
----------
6 | 7 | 8
*/

Player winner(Player[] board){

    foreach (var line in winLines){}
        var marks = line.select(e => board[e]);
        if (marks.unique().except(Player.None).size() == 1)
                return marks.first();
        }
    }
    return Player.None;
}

static int[][] winLines = {
    {0,1,2},
    {3,4,5},
    {6,7,8},
    {0,3,6},
    {1,4,7},
    {2,5,8},
    {0,4,8},
    {2,4,6}
    };

}