public int Minimax(bool isMax, int depth)
{
if (TicTacToeBoard.IsGameOver())
{
return(TicTacToeBoard.EvaluateWinningScore(depth));
}
var Scores = new List <int>();
var availableMoves = TicTacToeBoard.GetAvailablePositions();
//Calculate MIN and MAX scores
if (isMax)
{
foreach (var move in availableMoves)
{
// Make a move from the available
// user made move, now compo makes
TicTacToeBoard.Board[move.Item1, move.Item2] = MaxPlayer;
// Add the score of the that board
Scores.Add(Minimax(!isMax, depth++));
TicTacToeBoard.Board[move.Item1, move.Item2] = TicTacToeBoard.Player.E;
}
int maxScore = Scores.Max();
return(maxScore);
}
else
{
foreach (var move in availableMoves)
{
// Make a move from the available
// user made move, now compo makes
TicTacToeBoard.Board[move.Item1, move.Item2] = MinPlayer;
// Add the score of the that board
Scores.Add(Minimax(!isMax, depth++));
TicTacToeBoard.Board[move.Item1, move.Item2] = TicTacToeBoard.Player.E;
}
int minScore = Scores.Min();
return(minScore);
}
}
public void Play()
{
Console.WriteLine("Starting Tic-Tac-Toe game...");
Console.WriteLine("Choose a position on the board");
// The scores for each round
// Hard coded
MaxPlayer = TicTacToeBoard.Player.O;
MinPlayer = TicTacToeBoard.Player.X;
while (!TicTacToeBoard.IsFull())
{
var scores = new List <int>();
string humanMove = Console.ReadLine();
int row = Convert.ToInt32(humanMove.Split(',')[0]);
int column = Convert.ToInt32(humanMove.Split(',')[1]);
if (!TicTacToeBoard.IsValidCell(row, column) || !TicTacToeBoard.IsCellEmpty(row, column))
{
throw new ArgumentOutOfRangeException("Invalid positions.");
}
Console.WriteLine("\n");
TicTacToeBoard.Board[row, column] = TicTacToeBoard.Player.X;
TicTacToeBoard.Print();
Console.WriteLine("\n");
var availableMoves = TicTacToeBoard.GetAvailablePositions();
foreach (var currMove in availableMoves)
{
TicTacToeBoard.Board[currMove.Item1, currMove.Item2] = MaxPlayer;
int minimaxScore = Minimax(false, 0);
scores.Add(minimaxScore);
TicTacToeBoard.Board[currMove.Item1, currMove.Item2] = TicTacToeBoard.Player.E;
}
Console.WriteLine();
// User moved (min) -> Its computers move (should be max)
// For each avaiable move, call minimax
var index = scores.FindIndex(score => score == scores.Max());
if (index != -1)
{
var move = availableMoves[index];
TicTacToeBoard.Board[move.Item1, move.Item2] = TicTacToeBoard.Player.O;
TicTacToeBoard.Print();
}
string winner = TicTacToeBoard.HasWinner();
if (winner == "X")
{
Console.WriteLine("You win!");
break;
}
else if (winner == "O")
{
Console.WriteLine("Computer wins!");
break;
}
else if (winner == "-")
{
Console.WriteLine("It is a draw game!");
break;
}
}
}
