public PositionTree(Position position, CellState whoMoves, Dictionary <int, PositionTree> children)
{
Position = position;
WhoMoves = whoMoves;
Children = children;
if (Children.Any())
{
if (whoMoves == CellState.Cross)
{
Score = Children.Values.Max(c => c.Score);
}
else
{
Score = Children.Values.Min(c => c.Score);
}
Depth = Children.Values.Max(c => c.Depth) + 1;
if (whoMoves == CellState.Circle)
{
// this position resulted from the cross's move;
// recommended move for circles is the one with the minimum score
RecommendedMove = Children.Aggregate((curMin, x) => IsLess(x.Value, curMin.Value) ? x : curMin).Key;
}
}
else
{
Score = PositionScore.Of(position);
Depth = 1;
}
}
private PositionTree BuildTreeNoCache(Position position, CellState whoMoves)
{
if (!position.HasEmptyCells() || PositionScore.Of(position) != 0)
{
// final position, no children possible
return(new PositionTree(position, whoMoves, new Dictionary <int, PositionTree>()));
}
var otherSide = whoMoves == CellState.Cross ? CellState.Circle : CellState.Cross;
var children = new Dictionary <int, PositionTree>();
for (int cell = 0; cell < Position.TotalCells; ++cell)
{
if (position[cell] != CellState.Empty)
{
continue;
}
children[cell] = BuildTree(position.Move(cell, whoMoves), otherSide); // recursive call
}
return(new PositionTree(position, whoMoves, children));
}