private bool RemoveFromOtherBoxesInRegion(MutablePuzzle puzzle, Region region, SudokuValues value, int boxIndex)
{
var anyChanged = false;
for (int i = 0; i < Puzzle.LineLength; i++)
{
var coords = region.GetCoordinate(i);
if (coords.Box == boxIndex)
{
continue;
}
var cell = region[i];
if (!cell.IsSingle && cell.HasAnyOptions(value))
{
var update = new CellUpdate(value, coords);
puzzle.RemoveOptions(update);
anyChanged = true;
}
}
return(anyChanged);
}
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;
}
}
}
}
}
public void Apply(MutablePuzzle puzzle, RegionQueue changedRegions)
{
while (changedRegions.TryDequeue(puzzle, out var region))
{
var placedDigits = region.GetPlacedDigits();
FindTuple(puzzle, changedRegions, region, placedDigits);
}
}
private void FindTuple(MutablePuzzle puzzle, RegionQueue regions, Region region, SudokuValues placedDigits)
{
var combinations = Helpers.GetCombinationIndices(Puzzle.LineLength, _size);
for (int i = 0; i < combinations.Length; i++)
{
var comb = combinations[i];
if (placedDigits.HasAnyOptions(comb))
{
// skip any tuples that include placed digits
continue;
}
var positions = region.GetPositions(comb);
if (positions.GetOptionCount() != _size)
{
// these digits are placeable in more than tupleSize spots, so not hidden tuple
continue;
}
// we found a hidden tuple!
var options = ArrayPool <int> .Shared.Rent(Puzzle.LineLength);
var count = positions.CopyIndices(options);
var opposite = comb.Invert();
var anyChanged = false;
for (var index = 0; index < count; index++)
{
var cell = region[options[index]];
if (!cell.IsSingle && cell.HasAnyOptions(opposite))
{
var update = region.RemoveOptions(options[index], opposite);
puzzle.RemoveOptions(update);
anyChanged = true;
regions.Enqueue(RegionType.Row, update.Coordinate.Row);
regions.Enqueue(RegionType.Column, update.Coordinate.Column);
regions.Enqueue(RegionType.Box, update.Coordinate.Box);
}
}
ArrayPool <int> .Shared.Return(options);
if (anyChanged)
{
#if DEBUG
Program.Debugger.AddAction($"Hidden {comb} tuple in {region}");
#endif
return;
}
}
}
public bool TryDequeue(MutablePuzzle puzzle, out Region item)
{
if (TryDequeue(out var type, out var index))
{
item = puzzle.Puzzle.GetRegion(type, index);
return(true);
}
item = default;
return(false);
}
public void ApplyToPuzzle(MutablePuzzle puzzle)
{
throw new NotImplementedException();
}
public void Absorb(MutablePuzzle other)
{
Array.Copy(other._cells, _cells, _cells.Length);
_currentChangeSet.Queue.EnqueueAll(RegionQueue.GetFull());
}
private void FindTuple(MutablePuzzle puzzle, RegionQueue regions, Region region, SudokuValues placedDigits)
{
var combinations = Helpers.GetCombinationIndices(Puzzle.LineLength, _size);
for (int j = 0; j < combinations.Length; j++)
{
var comb = combinations[j];
if (placedDigits.HasAnyOptions(comb))
{
// skip any tuples that include placed digits
continue;
}
var indices = ArrayPool <int> .Shared.Rent(_size);
var count = comb.CopyIndices(indices);
var possibleValues = SudokuValues.None;
for (int i = 0; i < count; i++)
{
var cell = region[indices[i]];
possibleValues = possibleValues.AddOptions(cell);
}
ArrayPool <int> .Shared.Return(indices);
var optionsCount = possibleValues.GetOptionCount();
if (optionsCount == _size)
{
// we found a tuple!
for (var i = 0; i < Puzzle.LineLength; i++)
{
var otherCell = region[i];
if (otherCell.IsSingle)
{
continue;
}
if (!otherCell.HasAnyOptions(possibleValues))
{
continue;
}
if (comb.HasAnyOptions(SudokuValues.FromIndex(i)))
{
continue;
}
var newCell = region.RemoveOptions(i, possibleValues);
puzzle.RemoveOptions(newCell);
regions.Enqueue(RegionType.Row, newCell.Coordinate.Row);
regions.Enqueue(RegionType.Column, newCell.Coordinate.Column);
regions.Enqueue(RegionType.Box, newCell.Coordinate.Box);
#if DEBUG
Program.Debugger.AddAction($"{possibleValues} tuple in {region}.");
#endif
}
}
}
}