public IMove ABNegamax(IBoardGame game, int maxDepth, int currentDepth, double alfa, double beta)
{
if (maxDepth == currentDepth || game.GameIsOver())
return game.EvaluatePosition();
IMove bestMove = null;
var moves = (new RandomList<IMove>(game.GetLegalMoves())).Randomize();
foreach (var validMove in moves)
{
if (bestMove == null) bestMove = validMove;
IBoardGame testGame = game.TestMove(validMove);
validMove.SetMoveScore(-(ABNegamax(testGame, maxDepth, currentDepth + 1, -beta, -Math.Max(alfa, bestMove.GetMoveScore())).GetMoveScore()));
if (validMove.GetMoveScore() > bestMove.GetMoveScore())
{
bestMove = validMove;
}
if (bestMove.GetMoveScore() >= beta)
return bestMove;
}
return bestMove;
}
public IMove MiniMax(IBoardGame game, int maxDepth, double alfa, double beta)
{
if (maxDepth == 0)
return null;
IMove bestMove = null;
var moves = (new RandomList<IMove>(game.GetLegalMoves())).Randomize();
int color = game.GetCurrentPlayer().GetPlayerID();
foreach (var validMove in moves)
{
IBoardGame testGame = game.TestMove(validMove);
validMove.SetMoveScore(testGame.EvaluatePosition(game));
if (bestMove == null) bestMove = validMove;
if (!testGame.GameIsOver())
{
IMove nextBestMove = MiniMax(testGame, maxDepth - 1, alfa, beta);
if (nextBestMove != null) validMove.SetMoveScore(nextBestMove.GetMoveScore());
if (color == 1 && validMove.GetMoveScore() > beta)
{
beta = validMove.GetMoveScore();
}
if (color == -1 && validMove.GetMoveScore() < alfa)
{
alfa = validMove.GetMoveScore();
}
}
if (color == 1 && validMove.GetMoveScore() > alfa)
{
validMove.SetMoveScore(alfa);
return validMove;
}
if (color == -1 && validMove.GetMoveScore() < beta)
{
validMove.SetMoveScore(beta);
return validMove;
}
if (color * validMove.GetMoveScore() > color * bestMove.GetMoveScore())
bestMove = validMove;
}
return bestMove;
}
public List<IMove> EvaluateMoves(IBoardGame game, int maxDepth, int currentDepth, double alfa, double beta)
{
List<IMove> rankedMoveList = new List<IMove>();
var moves = (new RandomList<IMove>(game.GetLegalMoves())).Randomize();
foreach (var validMove in moves)
{
IBoardGame testGame = game.TestMove(validMove);
validMove.SetMoveScore(-(ABNegamax(testGame, maxDepth, currentDepth + 1, -beta, -alfa)).GetMoveScore());
int moveRank = 0;
foreach (var insertedMove in rankedMoveList)
{
if (validMove.GetMoveScore() < insertedMove.GetMoveScore())
moveRank++;
else break;
}
rankedMoveList.Insert(moveRank, validMove);
for (int index = 0; index < rankedMoveList.Count; index++)
{
rankedMoveList[index].SetRank(index);
}
}
return rankedMoveList;
}
