private void RecursiveSolve(SolverNode node, List<Matrix> solutions)
{
List<Cell> emptyCells = ListEmptyCells(node.MatrixState);
if (node.MatrixState.HasSolution && !node.MatrixState.IsResolved)
{
foreach (Cell emptyCell in emptyCells)
{
CalculatePossibilities(emptyCell, node.MatrixState);
if (emptyCell.Possibilities.Count == 1)
{
int foundedValue = emptyCell.Possibilities[0];
emptyCell.Value = foundedValue;
node.MatrixState.LoadValue(emptyCell.Coordinates, emptyCell.Value);
if (ValueAdded != null)
ValueAdded(this, new ValueChangedEventArgs(node.MatrixState));
RecursiveSolve(node, solutions);
if (solutions.Count == solutions.Capacity)
break;
if (!node.MatrixState.HasSolution)
{
node.Dispose();
node = null;
break;
}
}
}
}
if (emptyCells.Count == 0 && !node.MatrixState.IsResolved)
{
node.MatrixState.IsResolved = true;
if (!solutions.Contains(node.MatrixState, Matrix.Comparer) && solutions.Count < solutions.Capacity)
solutions.Add(node.MatrixState);
}
else
{
if (node != null && node.ChildNodes.Count == 0 && !node.MatrixState.IsResolved && node.MatrixState.HasSolution)
{
List<Cell> orderedEmptyCells = (from emptyCell in emptyCells orderby emptyCell.Possibilities.Count select emptyCell).ToList();
if (orderedEmptyCells.Count > 0)
{
Cell lessPossibilitiesCell = orderedEmptyCells[0];
if (lessPossibilitiesCell.Possibilities.Count > 0)
{
foreach (int possibility in lessPossibilitiesCell.Possibilities)
{
Matrix possibleState = new Matrix(node.MatrixState);
possibleState.LoadValue(lessPossibilitiesCell.Coordinates, possibility);
if (ValueAdded != null)
ValueAdded(this, new ValueChangedEventArgs(possibleState));
node.ChildNodes.Add(new SolverNode(possibleState));
}
int noSolutionCount = 0;
foreach (SolverNode childNode in node.ChildNodes)
{
RecursiveSolve(childNode, solutions);
if (solutions.Count == solutions.Capacity)
break;
if (!node.MatrixState.HasSolution)
{
node.Dispose();
node = null;
break;
}
if (!childNode.MatrixState.HasSolution)
{
noSolutionCount++;
}
}
if (node.ChildNodes.Count > 0 && node.ChildNodes.Count == noSolutionCount && !node.MatrixState.IsResolved)
{
node.MatrixState.HasSolution = false;
if (ValueRemoved != null)
ValueRemoved(this, new ValueChangedEventArgs(node.MatrixState));
}
}
else
{
node.MatrixState.HasSolution = false;
if (ValueRemoved != null)
ValueRemoved(this, new ValueChangedEventArgs(node.MatrixState));
}
}
else
{
node.MatrixState.HasSolution = false;
if (ValueRemoved != null)
ValueRemoved(this, new ValueChangedEventArgs(node.MatrixState));
}
}
}
}