def _split_groups(self):
"""
Split groups where possible.
A group of size :math:`n` can be split if there is a subgroup of size :math:`0 < k < n` cells in this group,
such that these cells have the same :math:`k` possible symbols. In this case, this group can be considered as
two different groups. The subgroup with a possible alphabet of the :math:`k` symbols, and the complementary
subgroup.
:return: ``True`` iff a change to the board was done.
:rtype: bool
"""
changed = False
possibles_to_group_to_cells = defaultdict(lambda: defaultdict(set))
for cell in self._iter_empty_cells():
group_to_symbols = possibles_to_group_to_cells[frozenset(cell.get_possible_symbols())]
for group in cell.iterate_groups():
group_to_symbols[group].add(cell)
# possibles_to_group_to_cells[possible_symbols, group].add(cell)
for possible_symbols, group_to_symbols in possibles_to_group_to_cells.iteritems():
for group, cells in group_to_symbols.iteritems():
if len(possible_symbols) == len(cells) and len(cells) != len(group.cells):
new_group = CellGroup(cells)
self._groups.append(new_group)
new_group.remove_as_subgroup(self._groups)
changed = True
break
else:
continue
break
return changed
def test_cell_group_is_valid_partially_empty_valid(alphabet10):
cells = [Cell(0, y, alphabet10) for y in xrange(10)]
group = CellGroup(set(cells))
cells[0].set_symbol('0')
cells[1].set_symbol('1')
assert group.is_valid()
def test_cell_group_contains_cells_false_addition(alphabet10):
cells = set([Cell(0, y, alphabet10) for y in xrange(10)])
group = CellGroup(set(cells))
cells.add(Cell(1, 0, alphabet10))
assert not group.contains_cells(cells)
def test_cell_group_contains_cells_false(alphabet10):
cells = [Cell(0, y, alphabet10) for y in xrange(10)]
group = CellGroup(set(cells))
assert not group.contains_cells(set([Cell(x, 0, alphabet10) for x in xrange(10)]))
def test_cell_group_contains_cells_true_part(alphabet10):
cells = [Cell(0, y, alphabet10) for y in xrange(10)]
group = CellGroup(set(cells))
assert group.contains_cells(set(cells[2:5]))
def test_cell_group_contains_cells_true_all(alphabet10):
cells = set([Cell(0, y, alphabet10) for y in xrange(10)])
group = CellGroup(set(cells))
assert group.contains_cells(cells)
def test_cell_group_is_valid_empty_cells(alphabet10):
cells = [Cell(0, y, alphabet10) for y in xrange(10)]
group = CellGroup(set(cells))
assert group.is_valid()