public SudokuBrett Solve(SudokuBrett sudokuBrett)
{
PossibleValues[,] set = sudokuBrett.InitPossibleValues();
IterativeSolveCells(sudokuBrett, set);
if (sudokuBrett.GetUnsolved() == 0) //success, solution found
{
return(sudokuBrett);
}
//if not solved, try..
if (sudokuBrett.GetUnsolved() > 0)
{
//find first posssible valueset..
var firstWithoutValue = set.FirstWithoutValue();
var orginal = new SudokuBrett(sudokuBrett);
foreach (var posssible in firstWithoutValue.value)
{
try
{
sudokuBrett.GuessSet(firstWithoutValue.r, firstWithoutValue.c, posssible);
sudokuBrett = Solve(sudokuBrett);
if (sudokuBrett.GetUnsolved() == 0) //success, solution found
{
return(sudokuBrett);
}
else
{
//didnt succesfully solved with this guessed number, try next...
sudokuBrett = orginal;
}
}
catch (Exception)
{
sudokuBrett = orginal;
}
}
}
//no solution found
return(sudokuBrett);
}
private void IterativeSolveCells(SudokuBrett sudokuBrett, PossibleValues[,] set)
{
int updated = 1;
while (updated > 0)
{
sudokuBrett.RemoveUsedFromPossibleValues(set);
set.ReducePossibleValues();
if (!sudokuBrett.IsLegal(set))
{
throw new Exception($"Illegal settings ");
}
updated = sudokuBrett.UpdateNextPossibleValues(set);
}
return;
}