private bool _TrySolve(SquareTracker <TPuzzle> tracker)
{
var puzzle = tracker.Puzzle;
if (puzzle.NumEmptySquares == 0)
{
return(true);
}
Coordinate c = tracker.GetBestCoordinateToGuess();
Span <int> possibleValues = stackalloc int[puzzle.Size];
int numPossible = tracker.PopulatePossibleValues(in c, possibleValues);
for (int i = 0; i < numPossible; ++i)
{
int possibleValue = possibleValues[i];
if (tracker.TrySet(in c, possibleValue))
{
if (_TrySolve(tracker))
{
return(true);
}
tracker.UnsetLast();
}
}
return(false);
}
private bool _TrySolve()
{
if (_tracker.Puzzle.NumEmptySquares == 0)
{
return(true);
}
Coordinate c = _tracker.GetBestCoordinateToGuess();
foreach (int possibleValue in _tracker.GetPossibleValues(in c))
{
if (_tracker.TrySet(in c, possibleValue))
{
if (_TrySolve())
{
return(true);
}
_tracker.UnsetLast();
}
}
return(false);
}
private bool _TrySolveRandomly(SquareTracker <TPuzzle> tracker, Random random)
{
if (tracker.Puzzle.NumEmptySquares == 0)
{
return(true);
}
Coordinate c = tracker.GetBestCoordinateToGuess();
Span <int> possibleValues = stackalloc int[tracker.Puzzle.Size];
int numPossible = tracker.PopulatePossibleValues(in c, possibleValues);
while (numPossible > 0)
{
int possibleValue = Spans.PopRandom(random, possibleValues[0..numPossible--]);
private static SolveStats _TryAllSolutions(SquareTracker tracker)
{
if (tracker.Puzzle.NumEmptySquares == 0)
{
return(new SolveStats()
{
NumSolutionsFound = 1,
});
}
Coordinate c = tracker.GetBestCoordinateToGuess();
List <int>?possibleValues = tracker.GetPossibleValues(in c);
if (possibleValues.Count == 1)
{
if (tracker.TrySet(in c, possibleValues[0]))
{
return(_TryAllSolutions(tracker));
}
return(new SolveStats());
}
return(_TryAllSolutionsWithGuess(tracker, c, possibleValues));
}
