void ItsUniqueSudoku(int index = 0)
{
if (index >= panelsWithNum.Count)
{
return;
}
Panel currentPanel = panelsWithNum[index];
int currentNum = currentPanel.GetCurrentNum();
currentPanel.EraseNumber();
emptyPanels.Add(currentPanel);
for (int i = 1; i <= 9; ++i)
{
currentPanel.SetCandidate(i);
if (CanBePlaced(currentPanel))
{
currentPanel.AddCandidate(i);
}
}
List <int> panelCandidates = currentPanel.GetListOfCandidates();
if (panelCandidates.Count > 1)
{
int numOfSolutions = 0;
for (int i = 0; i < panelCandidates.Count; ++i)
{
currentPanel.SetNumber(panelCandidates[i]);
if (SolveSudoku())
{
numOfSolutions++;
}
}
if (numOfSolutions > 1)
{
emptyPanels.Remove(currentPanel);
currentPanel.SetNumber(currentNum);
}
}
for (int i = 0; i < emptyPanels.Count; ++i)
{
emptyPanels[i].EraseNumber();
}
ItsUniqueSudoku(++index);
}