private void GoDeeper(Board currentBoard, int whichQueen)
{
List<int[]> safeSquares = currentBoard.GetFreeSquares(whichQueen);
int numSafeSquares = safeSquares.Count;
if ((numSafeSquares > 0) && (whichQueen < this.numberOfQueens))
{
foreach (int[] location in safeSquares)
{
Board newBoard = currentBoard.Clone();
newBoard.PlaceQueen(location);
this.GoDeeper(newBoard, whichQueen + 1);
}
}
else if ((numSafeSquares == 1) && (whichQueen == this.numberOfQueens))
{
List<int[]> locationInList = safeSquares;
int[] location = locationInList[0];
currentBoard.PlaceQueen(location);
string formattedSolution = this.FormatSolution(currentBoard);
this.solutionCallback(formattedSolution);
this.numberOfSolutions++;
}
else
{
return;
}
}
public int Solve(int _numberOfQueens, InputForm.SolutionCallback _solutionCallback)
{
this.numberOfQueens = _numberOfQueens;
this.solutionCallback = _solutionCallback;
Board cleanBoard = new Board(_numberOfQueens);
this.GoDeeper(cleanBoard, 1);
return this.numberOfSolutions;
}
private string FormatSolution(Board board)
{
string formattedSolution = "";
List<int[]> queenLocations = board.QueenLocations;
foreach (int[] location in queenLocations)
{
char x = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"[location[0]];
int y = location[1] + 1;
formattedSolution += string.Format("{0}{1} ", x, y);
}
return formattedSolution;
}
public Board Clone()
{
Board cloneBoard = new Board(this.size);
for (int col = 0; col < this.size; col++)
{
for (int row = 0; row < this.size; row++)
{
cloneBoard.state[col, row] = this.state[col, row];
}
}
foreach (int[] location in this.queenLocations)
{
cloneBoard.queenLocations.Add(location);
}
return cloneBoard;
}