public AlphaBetaReturnValue MinValue(CheckersBoard board, int alphaValue, int betaValue, PieceColor color, ref int currentDepth, ref int maxDepth, int maxDepthToSearchFor)
{
NodesGenerated++;
var v = new AlphaBetaReturnValue(PositiveInfinity, null, currentDepth + 1);
var moves = board.GetAllAvailableMoves(color).ToList().OrderByDescending(mr => mr.JumpResults.Count()).ToList();
var coTest = CutoffTest(board, currentDepth, maxDepthToSearchFor);
if (coTest.HasValue && coTest.Value || !moves.Any())
{
v.Value = Evaluate(board, color);
v.Depth = currentDepth;
return v;
}
if (!coTest.HasValue)
{
return null;
}
for (var i = 0; i < moves.Count; i++)
{
var m = moves[i];
board.MovePiece(m, color);
if (currentDepth == 0 && moves.Count == 1)
{
v.Move = m;
v.Value = Evaluate(board, color);
board.RevertMove(m, color);
return v;
}
var newDepth = currentDepth;
newDepth++;
var retVal = MaxValue(board, alphaValue, betaValue,
color == PieceColor.Black ? PieceColor.Red : PieceColor.Black, ref newDepth,
ref maxDepth, maxDepthToSearchFor);
if (retVal == null)
return null;
retVal.Move = m;
board.RevertMove(m, color);
if (retVal.Depth > maxDepth)
maxDepth = retVal.Depth;
if(retVal.Value < v.Value)
{
v.Value = retVal.Value;
v.Move = retVal.Move;
}
if (v.Value <= alphaValue)
{
NumberOfMinPrunes++;
return retVal;
}
betaValue = Math.Min(betaValue, v.Value);
}
return v;
}
