public List <IllegalMove> CalculateIllegalMoves()
{
List <IllegalMove> illegalPoints = new List <IllegalMove>();
bool[,] potentialMovesAlreadyChecked = new bool[15, 15]; //dynamic programming implementation
foreach (Stone stone in StonesToCheckAround)
{
//check the adjacent 8 positions around each stone on board to find potential illegal moves (instead of the entire board)
int startingX = Math.Max(0, stone.point.X - 2);
int endingX = Math.Min(GameConfiguration.BOARD_SIZE - 1, stone.point.X + 2);
int startingY = Math.Max(0, stone.point.Y - 2);
int endingY = Math.Min(GameConfiguration.BOARD_SIZE - 1, stone.point.Y + 2);
for (int x = startingX; x <= endingX; x++)
{
for (int y = startingY; y <= endingY; y++)
{
CurrentPointBeingChecked = Point.At(x, y);
if (potentialMovesAlreadyChecked[x, y])
{
continue; //already reached this point through a neighbour
}
if (RenjuBoard.GetPointOnBoardOccupancyState(CurrentPointBeingChecked) == OccupancyState.Black ||
RenjuBoard.GetPointOnBoardOccupancyState(CurrentPointBeingChecked) == OccupancyState.White)
{
continue; //can't move to an occupied position
}
if (MoveProducesFiveToWin(CurrentPointBeingChecked, OccupancyState.Black))
{
//stop checking; if it's a winning move, it's automatically allowed (make sure this move doesn't product overline though)
}
else if (MoveProducesOverline(CurrentPointBeingChecked))
{
illegalPoints.Add(new IllegalMove(CurrentPointBeingChecked, IllegalMoveReason.Overline));
}
else if (CountOpenThrees(CurrentPointBeingChecked) >= 2)
{
illegalPoints.Add(new IllegalMove(CurrentPointBeingChecked, IllegalMoveReason.Double3));
}
else if (CountOpenFours(CurrentPointBeingChecked) >= 2)
{
illegalPoints.Add(new IllegalMove(CurrentPointBeingChecked, IllegalMoveReason.Double4));
}
else
{
//unoccupied position AND not illegal move
potentialMovesAlreadyChecked[x, y] = true;
}
}
}
}
return(illegalPoints);
}
