def steps(sudoku: Sudoku) -> Iterator[Step]:
_sudoku = Sudoku(*sudoku.cells(), box_size=sudoku.box_size)
all_techniques: Tuple[Type[Technique], ...] = (
techniques.LoneSingle,
techniques.HiddenSingle,
techniques.NakedPair,
techniques.NakedTriplet,
techniques.LockedCandidate,
techniques.XYWing,
techniques.UniqueRectangle,
)
for step in techniques.BulkPencilMarking(_sudoku):
_sudoku.update(step.changes)
yield step
while not _sudoku.is_solved():
for technique in all_techniques:
try:
step = technique(_sudoku).first()
except techniques.NotFound:
continue
else:
_sudoku.update(step.changes)
yield step
break
else:
raise exceptions.Unsolvable
def _get_correct_cells(self) -> List[Cell]:
sudoku = Sudoku(*[c for c in self.sudoku.cells() if c.value],
box_size=self.sudoku.box_size)
all_techniques = (
BulkPencilMarking,
techniques.NakedPair,
techniques.NakedTriplet,
techniques.LockedCandidate,
techniques.XYWing,
techniques.UniqueRectangle,
)
for technique in all_techniques:
for result in technique(sudoku):
sudoku.update(result.changes)
return [cell for cell in sudoku.cells() if cell.candidates]
def eliminate(sudoku: Sudoku) -> Sudoku:
_sudoku = Sudoku(*sudoku.cells(), box_size=sudoku.box_size)
all_techniques = (
techniques.LoneSingle,
techniques.HiddenSingle,
)
for step in techniques.BulkPencilMarking(_sudoku):
_sudoku.update(step.changes)
has_result = True
while has_result:
for technique in all_techniques:
has_result = False
for step in technique(_sudoku):
_sudoku.update(step.changes)
has_result = True
return _sudoku
def rank(sudoku: Sudoku) -> int:
total_solutions = 0
total_branch_factor = 0
def count(sudoku: Sudoku) -> None:
nonlocal total_solutions
nonlocal total_branch_factor
_sudoku = solvers.eliminate(sudoku)
cells = sorted(
(cell for cell in _sudoku.cells() if not cell.value),
key=operator.attrgetter("candidates"),
)
for cell in cells:
branch_factor = len(cell.candidates)
for candidate in cell.candidates:
_sudoku.update([Cell(position=cell.position, value=candidate)])
try:
count(_sudoku)
except (exceptions.InvalidSudoku, exceptions.NoCandidates):
pass
else:
total_solutions += 1
if total_solutions > 1:
raise exceptions.MultipleSolutions
total_branch_factor += pow(branch_factor - 1, 2)
_sudoku.update([cell])
else:
raise exceptions.NoCandidates
try:
count(sudoku)
except exceptions.NoCandidates:
pass
return (total_branch_factor * 100) + sum(1 for c in sudoku.cells() if not c.value)