public static int minimax()
{
StateNode sn = new StateNode();
return(TupleToMove(sn.miniMax(Board.board, false)));
}
private int GenerateStates(StateNode root, int depth, bool isMaximizingPlayer, int alpha, int beta)
{
root.currentDepth = depth;
if (Logic.WinCheck(root.gs) || depth >= maxDepth)
{
return(Logic.EvaluateBoard(root.gs, depth));
}
if (isMaximizingPlayer)
{
root.minimaxValue = int.MinValue;
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (root.gs.state[i, j] != 'X' && root.gs.state[i, j] != 'O')
{
var copiedGameState = root.gs.Copy();
var position = copiedGameState.state[i, j];
copiedGameState.state[i, j] = player;
var newNode = new StateNode();
newNode.gs = copiedGameState;
newNode.parent = root;
root.children.Add(newNode);
newNode.action = Tuple.Create(i, j);
newNode.minimaxValue = GenerateStates(newNode, depth + 1, !isMaximizingPlayer, alpha, beta);
root.minimaxValue = Math.Max(root.minimaxValue, newNode.minimaxValue);
alpha = Math.Max(alpha, root.minimaxValue);
if (beta <= alpha)
{
break;
}
}
}
}
return(root.minimaxValue);
}
else
{
root.minimaxValue = int.MaxValue;
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (root.gs.state[i, j] != 'X' && root.gs.state[i, j] != 'O')
{
var copiedGameState = root.gs.Copy();
var position = copiedGameState.state[i, j];
copiedGameState.state[i, j] = computer;
var newNode = new StateNode();
newNode.gs = copiedGameState;
newNode.parent = root;
root.children.Add(newNode);
newNode.action = Tuple.Create(i, j);
newNode.minimaxValue = GenerateStates(newNode, depth + 1, !isMaximizingPlayer, alpha, beta);
root.minimaxValue = Math.Min(root.minimaxValue, newNode.minimaxValue);
beta = Math.Min(beta, root.minimaxValue);
if (beta <= alpha)
{
break;
}
}
}
}
return(root.minimaxValue);
}
}