// BACKTRACKING - posledna moznost
// otazka - treba ho? urcite mam zachytene vsetky moznosti
// riesenia sudoku??
private void backtracking()
{
// najde prvy volny tah a vyberie prvu moznost
// a riesi sudoku normalne
Stack <SudokuField[, ]> state = new Stack <SudokuField[, ]>();
Stack <FieldBacktrack> positions = new Stack <FieldBacktrack>();
FieldBacktrack pos = findFirstPosition();
while (IsSolved == false)
{
SudokuField[,] saved = deepCopy();
state.Push(saved);
positions.Push(pos);
// nastavi ziadanu moznost vyberu
try
{
setMark(pos.Row, pos.Col, pos.getPointingMark(fields), false);
}
catch (IndexOutOfRangeException)
{
break;
}
sudoku();
// sudoku musi byt ciste
if (isDirty())
{
restoreState(state.Pop());
pos = positions.Pop();
pos.increment(fields);
}
}
positions.Clear();
state.Clear();
}