public void Apply(MutablePuzzle puzzle, RegionQueue changedRegions)
{
while (changedRegions.TryDequeueOfType(RegionType.Box, out int boxIndex))
{
var box = puzzle.Puzzle.Boxes[boxIndex];
var placedDigits = box.GetPlacedDigits();
for (int digit = 1; digit <= Puzzle.LineLength; digit++)
{
var value = SudokuValues.FromHumanValue(digit);
if (placedDigits.HasAnyOptions(value))
{
continue;
}
var rows = SudokuValues.None;
var cols = SudokuValues.None;
for (var i = 0; i < Puzzle.LineLength; i++)
{
var cellValue = box[i];
var cellCoord = box.GetCoordinate(i);
if (!cellValue.IsSingle && cellValue.HasAnyOptions(value))
{
rows = rows.AddOptions(SudokuValues.FromIndex(cellCoord.Row));
cols = cols.AddOptions(SudokuValues.FromIndex(cellCoord.Column));
}
}
if (rows.IsSingle)
{
var region = puzzle.Puzzle.Rows[rows.ToIndex()];
var anyChanged = RemoveFromOtherBoxesInRegion(puzzle, region, value, boxIndex);
if (anyChanged)
{
#if DEBUG
Program.Debugger.AddAction($"{digit}s in {box} remove others in {region}.");
#endif
return;
}
}
if (cols.IsSingle)
{
var region = puzzle.Puzzle.Columns[cols.ToIndex()];
var anyChanged = RemoveFromOtherBoxesInRegion(puzzle, region, value, boxIndex);
if (anyChanged)
{
#if DEBUG
Program.Debugger.AddAction($"{digit}s in {box} remove others in {region}.");
#endif
return;
}
}
}
}
}
private void FindTuple(MutablePuzzle puzzle, RegionQueue regions, Region region, SudokuValues placedDigits)
{
var combinations = Helpers.GetCombinationIndices(Puzzle.LineLength, _size);
for (int j = 0; j < combinations.Length; j++)
{
var comb = combinations[j];
if (placedDigits.HasAnyOptions(comb))
{
// skip any tuples that include placed digits
continue;
}
var indices = ArrayPool <int> .Shared.Rent(_size);
var count = comb.CopyIndices(indices);
var possibleValues = SudokuValues.None;
for (int i = 0; i < count; i++)
{
var cell = region[indices[i]];
possibleValues = possibleValues.AddOptions(cell);
}
ArrayPool <int> .Shared.Return(indices);
var optionsCount = possibleValues.GetOptionCount();
if (optionsCount == _size)
{
// we found a tuple!
for (var i = 0; i < Puzzle.LineLength; i++)
{
var otherCell = region[i];
if (otherCell.IsSingle)
{
continue;
}
if (!otherCell.HasAnyOptions(possibleValues))
{
continue;
}
if (comb.HasAnyOptions(SudokuValues.FromIndex(i)))
{
continue;
}
var newCell = region.RemoveOptions(i, possibleValues);
puzzle.RemoveOptions(newCell);
regions.Enqueue(RegionType.Row, newCell.Coordinate.Row);
regions.Enqueue(RegionType.Column, newCell.Coordinate.Column);
regions.Enqueue(RegionType.Box, newCell.Coordinate.Box);
#if DEBUG
Program.Debugger.AddAction($"{possibleValues} tuple in {region}.");
#endif
}
}
}
}