public TicTacToeMove NegaMaxMove(TicTacToeBoard game)
{
List <Vector2> moves = game.FindBlankCells(game.Board);
float score;
TicTacToeMove bestMove = new TicTacToeMove();
TicTacToeBoard boardCopy = new TicTacToeBoard();
bestMove.Score = -10000;
int depth = 0;
foreach (Vector2 v in moves)
{
boardCopy.Board = game.CopyBoard(game.Board);
boardCopy.PlaceMarker(boardCopy.Board, Marker.X, v);
score = NegaMax(boardCopy, boardCopy.GetOppositeMarker(Marker.X), depth);
if (score >= bestMove.Score)
{
bestMove.Score = (int)score;
bestMove.Cell = v;
}
}
return(bestMove);
}
public int NegaMax(TicTacToeBoard game, Marker player, int depth)
{
int maxScore = -1;
int sign = 1;
if (game.CheckForWinner(game.Board, Marker.X)) // return score/move
{
return(StaticEvaluation(Marker.X));
}
else if (game.CheckForWinner(game.Board, Marker.O))
{
return(StaticEvaluation(Marker.O));
}
else if (game.CheckForDraw(game.Board)) //return score/move
{
return(StaticEvaluation(Marker.Blank));
}
if (player != Marker.X)
{
sign = -1;
}
List <Vector2> moves = game.FindBlankCells(game.Board);
TicTacToeBoard gameCopy = new TicTacToeBoard();
int score = 0;
foreach (Vector2 nextMove in moves)
{
gameCopy.Board = gameCopy.CopyBoard(game.Board);
gameCopy.PlaceMarker(gameCopy.Board, player, nextMove);
score = sign * NegaMax(gameCopy, gameCopy.GetOppositeMarker(player), depth + 1);
if (score > maxScore)
{
maxScore = score;
}
}
return(maxScore * sign);
}