public Move GetMove(SquareTypes[,] board)
{
int moveNum = 0;
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (board[i, j] != SquareTypes.N)
{
moveNum++;
}
}
}
//first move is always a corner
if (moveNum == 0)
{
return(new Move(0, 0));
}
//second move should be the center if free, else a corner
if (moveNum == 1)
{
if (board[1, 1] == SquareTypes.N)
{
return(new Move(1, 1));
}
return(new Move(0, 0));
}
//make a winning move if possible
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (board[i, j] != SquareTypes.N)
{
continue;
}
board[i, j] = SquareType;
var winner = TicTacToeGame.GetWinner(board);
board[i, j] = SquareTypes.N;
if (winner == SquareType)
{
return(new Move(i, j));
}
}
}
//if we can't win, check if there are any moves that we have to make
//to prevent ourselves from losing
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (board[i, j] != SquareTypes.N)
{
continue;
}
//set the move to the opponent's type
board[i, j] = SquareType == SquareTypes.X ? SquareTypes.O : SquareTypes.X;
var winner = TicTacToeGame.GetWinner(board);
board[i, j] = SquareTypes.N;
//if the opponent will win by moving here, move here to block them
if (winner != SquareTypes.N)
{
return(new Move(i, j));
}
}
}
//if we're here, that means we have made at least 1 move already and can't win
//nor lose in 1 move, so just make the optimal play which would be to a free
//corner that isn't blocked
Move move = null;
int max = -1;
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (board[i, j] != SquareTypes.N)
{
continue;
}
board[i, j] = SquareType;
int count = 0;
for (int m = 0; m < 3; m++)
{
for (int n = 0; n < 3; n++)
{
if (board[m, n] != SquareTypes.N)
{
continue;
}
board[m, n] = SquareType;
var winner = TicTacToeGame.GetWinner(board);
board[m, n] = SquareTypes.N;
if (winner == SquareType)
{
count++;
}
}
}
board[i, j] = SquareTypes.N;
if (count > max)
{
move = new Move(i, j);
max = count;
}
}
}
return(move);
}