public string GetBoardState(PositionPiece color)
{
char[] boardState = new char[19 * 19];
char available = '0';
char unavailable = '1';
char black = '2';
char white = '3';
GoPosition[] adjacentPositions = new GoPosition[4];
foreach (var position in positions)
{
char state = available;
if (position.piece == PositionPiece.Empty)
{
state = unavailable;
if (lastLiberties.ContainsKey(position))
{
GetAdjacentPositions(position, adjacentPositions);
foreach (var adjacent in adjacentPositions)
{
if ( adjacent.piece == PositionPiece.Empty ||
(adjacent.piece == color && !adjacent.group.hasManyLiberties) ||
(adjacent.piece != color && adjacent.group.hasManyLiberties))
{
state = available;
break;
}
}
}
else if (falseEyes.Contains(position))
{
GetAdjacentPositions(position, adjacentPositions);
if (adjacentPositions[0].piece != color)
{
state = available;
}
}
else
{
state = available;
}
}
else
{
state = position.piece == PositionPiece.Black ? black : white;
}
SetCharValue(state, position.rowIndex, position.colIndex, boardState);
}
return new String(boardState);
}
public GoBoardGroup(PositionPiece color)
{
this.groupColor = color;
this.piecesInGroup = new List<GoPosition>();
firstLiberty = null;
hasManyLiberties = false;
}
private void Reset(string boardState)
{
for (int rowIndex = 0; rowIndex < 18; rowIndex++)
{
for (int colIndex = 0; colIndex < 18; colIndex++)
{
int state = boardState[GetIndex(rowIndex, colIndex)];
PositionPiece piece = (state == '2' || state == '4') ? PositionPiece.Black : (state == '3' || state == '5') ? PositionPiece.White : PositionPiece.Empty;
positions[rowIndex, colIndex] = new GoPosition(rowIndex, colIndex, piece);
}
}
}
private void GetAdjacentPositions(GoPosition position, GoPosition[] adjacentPositions)
{
int rowIndex = position.rowIndex;
int colIndex = position.colIndex;
adjacentPositions[0] = positions[rowIndex, colIndex == 0 ? 17 : colIndex - 1];
adjacentPositions[1] = positions[rowIndex, colIndex == 17 ? 0 : colIndex + 1];
adjacentPositions[2] = positions[rowIndex == 0 ? 17 : rowIndex - 1, colIndex];
adjacentPositions[3] = positions[rowIndex == 17 ? 0 : rowIndex + 1, colIndex];
}
private void FindGroups()
{
GoPosition[] adjacentPositions = new GoPosition[4];
// Create the groups
for (int rowIndex = 0; rowIndex < 18; rowIndex++)
{
for (int colIndex = 0; colIndex < 18; colIndex++)
{
var position = positions[rowIndex, colIndex];
GetAdjacentPositions(position, adjacentPositions);
if (position.Piece == PositionPiece.Empty)
{
if (adjacentPositions[0].Piece != PositionPiece.Empty &&
adjacentPositions[0].Piece == adjacentPositions[1].Piece &&
adjacentPositions[1].Piece == adjacentPositions[2].Piece &&
adjacentPositions[2].Piece == adjacentPositions[3].Piece)
{
falseEyes.Add(position);
}
}
else if (position.group == null)
{
AddGroup(position);
}
}
}
}
private void AddGroup(GoPosition position)
{
GoPosition[] adjacentPositions = new GoPosition[4];
GoBoardGroup newGroup = new GoBoardGroup(position.piece);
Stack<GoPosition> newToGroup = new Stack<GoPosition>();
newToGroup.Push(position);
while (newToGroup.Count > 0)
{
var newPosition = newToGroup.Pop();
newPosition.group = newGroup;
GetAdjacentPositions(position, adjacentPositions);
foreach (GoPosition adjacent in adjacentPositions)
{
if (adjacent.group == null && adjacent.piece == newGroup.groupColor)
{
newToGroup.Push(adjacent);
}
if (!newGroup.hasManyLiberties && adjacent.piece == PositionPiece.Empty)
{
if (newGroup.firstLiberty == null)
{
newGroup.firstLiberty = adjacent;
}
else if (newGroup.firstLiberty != adjacent)
{
newGroup.hasManyLiberties = true;
}
}
}
newGroup.piecesInGroup.Add(newPosition);
}
groups.Add(newGroup);
if (!newGroup.hasManyLiberties && newGroup.firstLiberty != null)
{
if (!lastLiberties.ContainsKey(newGroup.firstLiberty))
{
lastLiberties.Add(newGroup.firstLiberty, new List<GoBoardGroup>());
}
lastLiberties[newGroup.firstLiberty].Add(newGroup);
}
else if (newGroup.firstLiberty == null)
{
deadGroups.Add(newGroup);
}
}