private Player DeterminePlayerColour(MinimaxPlayerType minimaxPlayerType)
{
if (whoAmI == Player.BLUE)
{
if (minimaxPlayerType == MinimaxPlayerType.MAX)
{
return(Player.BLUE);
}
else
{
return(Player.RED);
}
}
else
{
if (minimaxPlayerType == MinimaxPlayerType.MAX)
{
return(Player.RED);
}
else
{
return(Player.BLUE);
}
}
}
private int ConstructTree(MinimaxTreeNode parentNode, int depth, MinimaxPlayerType minimaxPlayer, int alpha, int beta)
{
// return estimation function if max tree depth reached or game is in finished state
if (depth == maxTreeDepth || parentNode.NonExistingLines.Count == 0)
{
return(EstimationFunction(parentNode));
}
if (minimaxPlayer == MinimaxPlayerType.MAX)
{
int bestValue = int.MinValue;
for (int i = 0; i < parentNode.NonExistingLines.Count; i++)
{
#region New Node Creation
MinimaxTreeNode node = new MinimaxTreeNode();
// calculate estimation function only for leaf nodes
node.Player = (parentNode.Player == MinimaxPlayerType.MAX ? MinimaxPlayerType.MIN : MinimaxPlayerType.MAX);
node.ExistingLines.AddRange(parentNode.ExistingLines);
node.ExistingLines.Add(parentNode.NonExistingLines[i]);
node.NonExistingLines.AddRange(parentNode.NonExistingLines);
node.NonExistingLines.Remove(parentNode.NonExistingLines[i]);
node.Boxes.AddRange(parentNode.Boxes);
List <Box> newBoxes = AICommon.TryClosingBoxes(parentNode.ExistingLines, DeterminePlayerColour(node.Player), parentNode.NonExistingLines[i], out int[] notUsed);
node.Boxes.AddRange(newBoxes);
node.DeltaMove = parentNode.NonExistingLines[i];
#endregion
/* don't go through this subtree if the delta move is drawing third edge
* unless it the only move
*/
AICommon.TryClosingBoxes(node.ExistingLines,
DeterminePlayerColour(node.Player),
node.DeltaMove,
out int[] surroundingEdges);
if ((surroundingEdges[0] == 2 || surroundingEdges[1] == 2))
{
if (!(i == parentNode.NonExistingLines.Count - 1 && parentNode.Children.Count == 0))
{
Debug.WriteLine(node.DeltaMove.ToString() + " was thrown.");
continue;
}
}
node.EstimationScore = ConstructTree(node, depth + 1, MinimaxPlayerType.MIN, alpha, beta);
bestValue = (bestValue > node.EstimationScore ? bestValue : node.EstimationScore);
alpha = (alpha > bestValue ? alpha : bestValue);
parentNode.Children.Add(node);
if (beta <= alpha)
{
break;
}
}
parentNode.EstimationScore = bestValue;
return(bestValue);
}
else
{
int bestValue = int.MaxValue;
for (int i = 0; i < parentNode.NonExistingLines.Count; i++)
{
#region New Node Creation
MinimaxTreeNode node = new MinimaxTreeNode();
// calculate estimation function only for leaf nodes
node.Player = (parentNode.Player == MinimaxPlayerType.MAX ? MinimaxPlayerType.MIN : MinimaxPlayerType.MAX);
node.ExistingLines.AddRange(parentNode.ExistingLines);
node.ExistingLines.Add(parentNode.NonExistingLines[i]);
node.NonExistingLines.AddRange(parentNode.NonExistingLines);
node.NonExistingLines.Remove(parentNode.NonExistingLines[i]);
node.Boxes.AddRange(parentNode.Boxes);
List <Box> newBoxes = AICommon.TryClosingBoxes(parentNode.ExistingLines, DeterminePlayerColour(node.Player), parentNode.NonExistingLines[i], out int[] notUsed);
node.Boxes.AddRange(newBoxes);
node.DeltaMove = parentNode.NonExistingLines[i];
#endregion
/* don't go through this subtree if the delta move is drawing third edge
* unless it the only move
*/
AICommon.TryClosingBoxes(node.ExistingLines,
DeterminePlayerColour(node.Player),
node.DeltaMove,
out int[] surroundingEdges);
if ((surroundingEdges[0] == 2 || surroundingEdges[1] == 2))
{
if (!(i == parentNode.NonExistingLines.Count - 1 && parentNode.Children.Count == 0))
{
Debug.WriteLine(node.DeltaMove.ToString() + " was thrown.");
continue;
}
}
node.EstimationScore = ConstructTree(node, depth + 1, MinimaxPlayerType.MAX, alpha, beta);
bestValue = (bestValue < node.EstimationScore ? bestValue : node.EstimationScore);
beta = (beta < bestValue ? beta : bestValue);
parentNode.Children.Add(node);
if (beta <= alpha)
{
break;
}
}
parentNode.EstimationScore = bestValue;
return(bestValue);
}
throw new Exception("Something wrong in minimax happened");
}
