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);
}
public SolveStats GetStatsForAllSolutions(TPuzzle puzzle)
{
if (!_AreValuesUnique(puzzle.AllPossibleValues))
{
throw new ArgumentException(
$"{nameof(puzzle.AllPossibleValues)} must all be unique. Received values: {puzzle.AllPossibleValues.ToString()}.");
}
var puzzleCopy = (TPuzzle)puzzle.DeepCopy();
var matrix = new ExactCoverMatrix(puzzleCopy);
foreach (IConstraint?constraint in _constraints)
{
constraint.Constrain(puzzleCopy, matrix);
}
return(_TryAllSolutions(new SquareTracker <TPuzzle>(puzzleCopy, matrix)));
}
public static ConstraintHeader CreateConnectedHeader(
ExactCoverMatrix matrix, ReadOnlySpan <PossibleValue> possibleSquares)
{
var header = new ConstraintHeader(matrix);
matrix.Attach(header);
foreach (PossibleValue?possibleSquare in possibleSquares)
{
_ = Link.CreateConnectedLink(possibleSquare, header);
}
if (header.Count == 0)
{
throw new ArgumentException(
$"Must provide at least one {nameof(PossibleValue)} when creating a {nameof(ConstraintHeader)}.");
}
return(header);
}
internal ConstraintHeader CopyToMatrix(ExactCoverMatrix matrix)
{
Debug.Assert(FirstLink != null, $"Can't copy a header with a null {nameof(FirstLink)}.");
Debug.Assert(!IsSatisfied, $"Can't copy a header that's already satisfied.");
var copy = new ConstraintHeader(matrix);
foreach (Link?link in GetLinks())
{
Square?square = matrix.GetSquare(link.PossibleSquare.Square.Coordinate);
Debug.Assert(square != null,
$"Tried to copy a square link for a null square at {link.PossibleSquare.Square.Coordinate}.");
PossibleValue?possibleSquare = square.GetPossibleValue(link.PossibleSquare.ValueIndex);
Debug.Assert(possibleSquare != null, "Tried to link header to null possible square value.");
_ = Link.CreateConnectedLink(possibleSquare, copy);
}
return(copy);
}
public void SolveRandomly(TPuzzle puzzle)
{
if (!_AreValuesUnique(puzzle.AllPossibleValues))
{
throw new ArgumentException(
$"{nameof(puzzle.AllPossibleValues)} must all be unique. Received values: {puzzle.AllPossibleValues.ToString()}.");
}
var matrix = new ExactCoverMatrix(puzzle);
foreach (IConstraint?constraint in _constraints)
{
constraint.Constrain(puzzle, matrix);
}
if (!_TrySolveRandomly(new Random(), new SquareTracker <TPuzzle>(puzzle, matrix)))
{
throw new ArgumentException($"Failed to solve the given puzzle.");
}
}
internal ConstraintHeader(ExactCoverMatrix matrix)
{
Matrix = matrix;
NextHeader = PreviousHeader = this;
}
internal SquareTracker(TPuzzle puzzle, ExactCoverMatrix matrix)
{
_puzzle = puzzle;
_matrix = matrix;
_setCoords = new Stack <Coordinate>(puzzle.NumEmptySquares);
}