private MapNodeDecisionTree BuildDecisionTree(MapNode head, int recurseLevel)
{
MapNodeDecisionTree decisionNode = new MapNodeDecisionTree(head);
if (recurseLevel > 0)
{
foreach (MapNode neighbor in head.GetNeighbors().Distinct(new MapNodeColorComparer()))
{
MapNode headClone = head.Clone();
headClone.PickColor(neighbor.Color); //make the move
MapNodeDecisionTree childNode = BuildDecisionTree(headClone, recurseLevel - 1);
decisionNode.Children.Add(childNode);
}
}
return(decisionNode);
}
/// <summary>
/// Walks down each "branch" of the currentDecisionTree to see which has the best surface area
/// </summary>
/// <param name="currentDecisionTree"></param>
/// <param name="bestSurfaceArea"></param>
/// <param name="highestColorStack"></param>
/// <returns>The colors that result in the highest decision tree</returns>
private SurfaceAreaResult GetBest(MapNodeDecisionTree currentDecisionTree, SurfaceAreaResult bestSurfaceArea, Stack <Color> highestColorStack)
{
highestColorStack.Push(currentDecisionTree.Color); //mirror the execution stack
if (GetSurfaceArea(currentDecisionTree.CurrentMap) > bestSurfaceArea.SurfaceArea)
{
bestSurfaceArea.SurfaceArea = GetSurfaceArea(currentDecisionTree.CurrentMap);
bestSurfaceArea.Path = highestColorStack.ToArray();
}
foreach (MapNodeDecisionTree decisionTreeChild in currentDecisionTree.Children)
{
SurfaceAreaResult childSurfaceArea = GetBest(decisionTreeChild, bestSurfaceArea, highestColorStack);
if (childSurfaceArea.SurfaceArea > bestSurfaceArea.SurfaceArea)
{
bestSurfaceArea = childSurfaceArea;
}
}
highestColorStack.Pop(); //mirror the execution stack
return(bestSurfaceArea);
}
public override SuggestedMoves ChooseColor(Color[,] board)
{
MapNode head = MapBuilder.BuildMap(board);
MapNodeDecisionTree decisionTree = BuildDecisionTree(head.Clone(), _lookAheadLevel);
Stack <Color> currentDecisionTreePath = new Stack <Color>();
SurfaceAreaResult bestSurfaceArea = GetBest(decisionTree, new SurfaceAreaResult {
SurfaceArea = 0, Path = new Color[0]
}, currentDecisionTreePath);
//convert the result to SuggestedMove
SuggestedMoves moves = new SuggestedMoves();
for (int i = 0; i < bestSurfaceArea.Path.Length - 1; i++)
{
moves.AddFirst(new SuggestedMove(bestSurfaceArea.Path[i]));
}
return(moves);
}
