public void AIMakeTurn(int ply, Board b, int turn)
{
PossibleMove move = this.ProduceBest(ply, b, turn);
// Debug.Log("move = " + move.x + "," + move.y);
b.AddPiece(move.x, move.y, turn);
AI.TakeTurn(move.x, move.y, turn, b);
}
public PossibleMove AlphaBeta
(BoardNode node, int depth, PossibleMove alpha, PossibleMove beta, bool maximizingPlayer)
{
if (depth == 0) // || node.IsLeaf) {
// Debug.Log("node._move[0] = " + node._move.x);
// test node collection here
{
return(new PossibleMove(node._move.x, node._move.y, BoardNode.GetHeuristicValue(node, depth)));
}
if (maximizingPlayer == true)
{
// Debug.Log("Max");
List <PossibleMove> childs = CheckLegalMoves(node._bData, 1);
// List<BoardNode> children = BoardNode.GetChildren(node, 1);
PossibleMove score;
foreach (PossibleMove kid in childs)
{
var bn = BoardNode.GetChild(node._bData, kid, 1);
score = AlphaBeta(bn, depth - 1, alpha, beta, !maximizingPlayer);
alpha = alpha.score == Mathf.Max(alpha.score, score.score) ? alpha : score;
alpha.x = kid.x;
alpha.y = kid.y;
if (beta.score <= alpha.score)
{
break; // beta cut-off
}
}
// Debug.Log("alpha = " + alpha.score);
return(alpha);
}
else
{
// Debug.Log("Min");
List <PossibleMove> childs = CheckLegalMoves(node._bData, 0);
// List<BoardNode> children = BoardNode.GetChildren(node, 0);
PossibleMove score;
foreach (PossibleMove kid in childs)
{
var bn = BoardNode.GetChild(node._bData, kid, 0);
score = AlphaBeta(bn, depth - 1, alpha, beta, !maximizingPlayer);
beta = beta.score == Mathf.Min(beta.score, score.score) ? beta : score; // beta = min(beta,score)
beta.x = kid.x;
beta.y = kid.y;
if (beta.score <= alpha.score)
{
break; // alpha cut-off
}
}
// Debug.Log("beta = " + beta.score);
return(beta);
}
}
// randomize list function
public static void ShufflePossibleMovesList(List <PossibleMove> list)
{
System.Random rng = new System.Random();
int n = list.Count;
while (n > 1)
{
n--;
int k = rng.Next(n - 1);
PossibleMove value = list[k];
list[k] = list[n];
list[n] = value;
}
}
public static List <PossibleMove> CheckLegalMoves(Board b, int turn)
{
var legal = new List <PossibleMove>();
for (int i = 0; i < b._size; i++)
{
for (int j = 0; j < b._size; j++)
{
if (CheckCurrent(i, j, turn, b))
{
PossibleMove temp = new PossibleMove(i, j, int.MinValue);
legal.Add(temp);
}
}
}
AI.ShufflePossibleMovesList(legal);
return(legal);
}
public PossibleMove ProduceBest(int level, Board b, int color)
{
// ensure a current working board
Board scratchBoard = new Board(b._size);
Board.CopyBoard(scratchBoard, b);
BoardNode root = new BoardNode(scratchBoard);
// root._turn = (color == 1) ? 0 : 1;
// Start alphabeta algorithm and store the best H value
PossibleMove bestH =
this.AlphaBeta(root, level, new PossibleMove(-1, -1, int.MinValue),
new PossibleMove(-1, -1, int.MaxValue), true);
// Debug.Log("ProduceBest = " + bestH.x + ", " + bestH.y + ", score = " + bestH.score);
return(bestH);
}