/// <summary>
/// The territory of a player are those empty points on the board which are entirely surrounded by his live stones.
/// This method adds up total territory of players. The scores include prisoners and dead stones.
/// </summary>
/// <param name="currentNode">Node of tree representing the previous move.</param>
/// <param name="deadPositions">Positions marked as dead.</param>
/// <returns>The score of players, which does not include number of prisoners and dead stones.</returns>
protected Scores CountTerritory(GameTreeNode currentNode, IEnumerable <Position> deadPositions)
{
Scores scores = new Scores(0, 0);
//prisoners
IEnumerable <GameTreeNode> history = currentNode.GetNodeHistory();
foreach (GameTreeNode node in history)
{
if (node.Move.Captures.Count != 0)
{
if (node.Move.WhoMoves == StoneColor.Black)
{
scores.WhiteScore -= node.Move.Captures.Count;
}
else if (node.Move.WhoMoves == StoneColor.White)
{
scores.BlackScore -= node.Move.Captures.Count;
}
}
}
//dead stones
foreach (Position position in deadPositions)
{
if (RulesetInfo.BoardState[position.X, position.Y] == StoneColor.Black)
{
scores.BlackScore--;
}
else if (RulesetInfo.BoardState[position.X, position.Y] == StoneColor.White)
{
scores.WhiteScore--;
}
}
//regions
Scores regionScores = GetRegionScores(currentNode, deadPositions);
scores.WhiteScore += regionScores.WhiteScore;
scores.BlackScore += regionScores.BlackScore;
return(scores);
}
/// <summary>
/// The area of a player are all live stones of player left on the board together with any points of his territory. In this case, prisoners are ignored.
/// This method adds up total area of players.
/// </summary>
/// <param name="currentNode">Node of tree representing the previous move.</param>
/// <param name="deadPositions">Positions marked as dead.</param>
/// <returns>The score of players.</returns>
protected Scores CountArea(GameTreeNode currentNode, IEnumerable <Position> deadPositions)
{
Scores scores = GetRegionScores(currentNode, deadPositions);
for (int i = 0; i < RulesetInfo.BoardSize.Width; i++)
{
for (int j = 0; j < RulesetInfo.BoardSize.Height; j++)
{
if (RulesetInfo.BoardState[i, j] == StoneColor.Black)
{
scores.BlackScore++;
}
else if (RulesetInfo.BoardState[i, j] == StoneColor.White)
{
scores.WhiteScore++;
}
}
}
return(scores);
}
/// <summary>
/// Returns the scores after adding up total territory of players.
/// </summary>
/// <param name="currentNode">Node of tree representing the previous move.</param>
/// <param name="deadPositions">Positions marked as dead.</param>
/// <returns>The score of players, which includes number of prisoners and dead stones yet.</returns>
private Scores GetRegionScores(GameTreeNode currentNode, IEnumerable <Position> deadPositions)
{
RulesetInfo.SetBoard(currentNode.BoardState.BoardWithoutTheseStones(deadPositions));
Scores scores = new Scores(0, 0);
Territory[,] regions = DetermineTerritory(RulesetInfo.BoardState);
for (int i = 0; i < RulesetInfo.BoardSize.Width; i++)
{
for (int j = 0; j < RulesetInfo.BoardSize.Height; j++)
{
if (regions[i, j] == Territory.Black)
{
scores.BlackScore++;
}
else if (regions[i, j] == Territory.White)
{
scores.WhiteScore++;
}
}
}
return(scores);
}
