private (Player Winner, int[] Positions)? DetectGameOver()
{
// check vertical for winner
for (var i = 0; i < 3; i++)
{
var vertWin = CheckLine(i, i + 3, i + 6);
if (vertWin.Winner != Player.Nobody)
{
return(vertWin);
}
}
// check horizontal for winner
for (var i = 0; i < 9; i += 3)
{
var horizWin = CheckLine(i, i + 1, i + 2);
if (horizWin.Winner != Player.Nobody)
{
return(horizWin);
}
}
// check top-left to bottom-right for winner
var diag1Win = CheckLine(0, 4, 8);
if (diag1Win.Winner != Player.Nobody)
{
return(diag1Win);
}
// check top-right to bottom-left for winner
var diag2Win = CheckLine(2, 4, 6);
if (diag2Win.Winner != Player.Nobody)
{
return(diag2Win);
}
// check tie
if (Board.All(b => b != Player.Nobody))
{
return(Player.Nobody, new int[0]);
}
return(null);
(Player Winner, int[] Positions) CheckLine(int a, int b, int c)
{
if (Board[a] == Board[b] && Board[a] == Board[c])
{
return(Board[a], new[] { a, b, c });
}
return(Player.Nobody, new int[0]);
}
}
