//static Dictionary<Game, SearchResultInfo> _games = new Dictionary<Game, SearchResultInfo>();
public static unsafe SearchResultInfo Search(uint depth, bool isMax, Game theGame, int alpha, int beta)
{
Game.Logger($"-----------------Start searching depth = {depth} alpha = {alpha}------------------");
theGame.LogGrid();
if (isMax)
{
if (depth == 0)
{
Game.Logger($"Depth = 0, score : {Evaluate(theGame, depth)}");
return new SearchResultInfo
{
Score = Evaluate(theGame, depth)
};
}
var newGame = new Game(theGame);
Direction? bestMove = null;
foreach (var direction in Directions)
{
Game.Logger($"Searching {direction}");
//var game = new Game(theGame);
var res = newGame.Update(direction);
if (res.HasMoved)
{
if (res.HasWon)
return new SearchResultInfo
{
Score = int.MaxValue,
MoveDirection = direction
};
else
{
Game.Logger("Searching down by max.");
var result = Search(depth - 1, false, newGame, alpha, beta);
if (result.Score > alpha)
{
bestMove = direction;
alpha = result.Score;
if (alpha >= beta)
break;
}
}
}
newGame.Reset(theGame);
}
Game.Logger($"result = {alpha} {bestMove}");
return new SearchResultInfo
{
Score = alpha,
MoveDirection = bestMove
};
}
else
{
var bitmap = theGame.GetBitmap();
var ptr = stackalloc int[48];
var cellScores = new StaticList(ptr);
var emptyCells = new StaticList(ptr + 16);
int lowestScore = int.MaxValue;
for (int i = 0; i < 16; ++i)
{
ushort mask = (ushort)(1 << i);
if((bitmap & mask) == 0)
{
var x = i / 4;
var y = i % 4;
theGame.AddCellTrivial(x, y, 1);
var score = theGame.Smoothness() - theGame.Dispersion();
Game.Logger($"Add cell at {x}, {y} gets score {score}, Smooth = {theGame.Smoothness()}, Monotonic = {theGame.Monotonicity()} Dispersion = {theGame.Dispersion()}");
theGame.LogGrid();
cellScores.Add(score);
lowestScore = Math.Min(score, lowestScore);
theGame.RemoveCellTrivial(x, y);
emptyCells.Add(i);
}
}
var lowestCells = new StaticList(ptr + 32);
for (int i = 0; i < emptyCells.Count; ++i)
{
if (cellScores[i] == lowestScore)
lowestCells.Add(emptyCells[i]);
}
for(int i = 0; i < lowestCells.Count; ++i)
{
var cell = lowestCells[i];
Game.Logger($"Add cell at {cell}, score is {lowestScore}");
var x = cell / 4;
var y = cell % 4;
theGame.AddCellTrivial(x, y, 1);
Game.Logger("Searching down by min.");
var result = Search(depth, true, theGame, alpha, beta);
theGame.RemoveCellTrivial(x, y);
if (result.Score < beta)
{
beta = result.Score;
Game.Logger($"Beta updated {beta}");
if (alpha >= beta)
{
Game.Logger("Cutoff");
break;
}
}
}
return new SearchResultInfo
{
Score = beta,
MoveDirection = null
};
}
}