private SquareTracker(SquareTracker <TPuzzle> other)
{
// Puzzle is guaranteed to be of type TPuzzle.
_puzzle = (TPuzzle)other._puzzle.DeepCopy();
// Copy matrix, focusing only on 'Unknown' possible square values and (therefore) unsatisfied constraints.
_matrix = other._matrix.CopyUnknowns();
_setCoords = new Stack <Coordinate>(_puzzle.NumEmptySquares);
}
private static SolveStats _TryAllSolutions(SquareTracker <TPuzzle> tracker)
{
if (tracker.IsSolved)
{
return(new SolveStats()
{
NumSolutionsFound = 1
});
}
(Coordinate c, int[]? possibleValues) = tracker.GetBestGuess();
if (possibleValues.Length == 1)
{
if (tracker.TrySet(in c, possibleValues[0]))
{
return(_TryAllSolutions(tracker));
}
return(new SolveStats());
}
return(_TryAllSolutionsWithGuess(in c, possibleValues, tracker));
}
private static bool _TrySolve(SquareTracker <TPuzzle> tracker)
{
if (tracker.IsSolved)
{
return(true);
}
(Coordinate c, int[]? possibleValues) = tracker.GetBestGuess();
foreach (int possibleValue in possibleValues)
{
if (tracker.TrySet(in c, possibleValue))
{
if (_TrySolve(tracker))
{
return(true);
}
tracker.UnsetLast();
}
}
return(false);
}
private static bool _TrySolveRandomly(Random rand, SquareTracker <TPuzzle> tracker)
{
if (tracker.IsSolved)
{
return(true);
}
(Coordinate c, int[]? possibleValues) = tracker.GetBestGuess();
var possibleValuesList = new List <int>(possibleValues);
while (possibleValuesList.Count > 0)
{
int possibleValue = possibleValuesList[rand.Next(0, possibleValuesList.Count)];
if (tracker.TrySet(in c, possibleValue))
{
if (_TrySolveRandomly(rand, tracker))
{
return(true);
}
tracker.UnsetLast();
}
_ = possibleValuesList.Remove(possibleValue);
}
return(false);
}
