private double MinMax(TileStateEnum[][] parentGameState, PawnLightModel move, int depth, bool maximizingPlayer)
{
VisitedNodesCount++;
var gameStateClone = DeepCloneGameState(parentGameState);
var capturedTiles = ReversiHelpers.PlacePawn(gameStateClone, move.State, move.X, move.Y);
var nextMovePlayer = move.State == TileStateEnum.Black ? TileStateEnum.White : TileStateEnum.Black;
var possiblePawnPlacements = ReversiHelpers.GetPossiblePawnPlacements(gameStateClone, nextMovePlayer);
var pgs = new PotentialGameState(move)
{
CapturedTiles = capturedTiles,
PossibleMoves = possiblePawnPlacements.Length
};
if (depth == 0)
{
return(pgs.GetNiceness(CurrentStrategy));
}
if (possiblePawnPlacements.Length == 0)
{
return(pgs.GetNiceness(CurrentStrategy));
}
double bestMove;
if (maximizingPlayer)
{
bestMove = double.NegativeInfinity;
foreach (var possibleMove in possiblePawnPlacements)
{
var moveResult = MinMax(gameStateClone, possibleMove, depth - 1, false);
if (moveResult > bestMove)
{
bestMove = moveResult;
}
}
}
else
{
bestMove = double.PositiveInfinity;
foreach (var possibleMove in possiblePawnPlacements)
{
var moveResult = MinMax(gameStateClone, possibleMove, depth - 1, true);
if (moveResult < bestMove)
{
bestMove = moveResult;
}
}
}
return(bestMove);
}
public override AiPlayerResult FindNextMove(Tile[][] gameState)
{
VisitedNodesCount = 0;
for (var i = 0; i < _currentBoardState.Length; i++)
{
for (var j = 0; j < _currentBoardState[i].Length; j++)
{
_currentBoardState[i][j] = gameState[i][j].State;
}
}
var gameStateClone = DeepCloneGameState(_currentBoardState);
var possiblePawnPlacements = ReversiHelpers.GetPossiblePawnPlacements(gameStateClone, _playerColor);
PawnLightModel bestMove = null;
var nicestNiceness = double.NegativeInfinity;
foreach (var possibleMove in possiblePawnPlacements)
{
var moveNiceness = MinMax(gameStateClone, possibleMove, _searchDepth, true);
if (!(moveNiceness > nicestNiceness))
{
continue;
}
nicestNiceness = moveNiceness;
bestMove = possibleMove;
}
var result = new AiPlayerResult()
{
Move = bestMove,
SearchedNodes = VisitedNodesCount
};
return(result);
}
/// <summary>
/// Creates new game state and remembers which pawn was placed this turn
/// gameState should have pawn already placed and game state should be valid
/// </summary>
/// <param name="gameState"></param>
/// <param name="moveMade"></param>
public PotentialGameState(PawnLightModel moveMade)
{
MoveMade = moveMade;
}
