def test_srow_contains_element_not_in_u(example):
extra = 10
subset = 'B'
example['s'][subset].add(extra)
with pytest.raises(ExactCoverKeyError) as e:
solve(example['u'], example['s'])
assert (f'ExactCoverKeyError: Element {repr(extra)} in '
f'subsets_rows {repr(subset)} is not in Universe') == str(e.value)
def test_solution_in_single_srow(example):
example['s']['A'] = set()
example['s']['B'] = {1, 2, 3, 4, 5, 6, 7}
example['s']['C'] = set()
example['s']['D'] = set()
example['s']['E'] = set()
example['s']['F'] = set()
assert [{'B'}] == solve(example['u'], example['s'])
def test_limit1_random_multiple_solutions(small_example):
counts_ab = 0
counts_cd = 0
size = 100
for i in range(size):
result = solve(small_example['u'],
small_example['s'],
limit=1,
randomize=True)
if [{'A', 'B'}] == result:
counts_ab += 1
if [{'C', 'D'}] == result:
counts_cd += 1
assert counts_ab != 0 and counts_cd != 0
def test_limit1_nonrandom_multiple_solutions(small_example):
size = 100
counts = {}
for i in range(size):
result = tuple(
sorted(
list(
solve(small_example['u'],
small_example['s'],
limit=1,
randomize=False).pop())))
if result not in counts:
counts[result] = 1
else:
counts[result] += 1
assert len(counts) == 1 and counts[result] == size
def test_count_preseed_2solutionTo0count(example):
example['s']['G'] = {3, 5, 6}
result = solve(example['u'], example['s'], preseed={'A'}, count=True)
assert 0 == result
def test_count_ignore(example):
example['s']['G'] = {3, 5, 6}
result = solve(example['u'], example['s'], count=3)
assert [{'B', 'D', 'F'}, {'B', 'F', 'G'}] == result
def test_limitneg1_multiple_solutions(example):
example['s']['G'] = {3, 5, 6}
result = solve(example['u'], example['s'], limit=-1)
assert [{'B', 'D', 'F'}, {'B', 'G', 'F'}] == result
def test_no_solution(example):
example['s']['D'].remove(6)
example['s']['E'].remove(6)
assert [] == solve(example['u'], example['s'])
def test_accept_str_u(trivial):
s = {k: set([str(x) for x in v]) for k, v in trivial['s'].items()}
assert isinstance(solve(''.join(map(str, trivial['u'])), s), list)
def test_accept_dict_u(trivial):
assert isinstance(solve({x: x for x in trivial['u']}, trivial['s']), list)
def test_preseed_contains_mix_invalid_correct(example):
fill = 'G'
with pytest.raises(ExactCoverKeyError) as e:
solve(example['u'], example['s'], preseed={fill, 'B'})
assert (f'ExactCoverKeyError: Element {repr(fill)} in preseed '
f'is not in subsets_rows') == str(e.value)
def test_preseed_contains_mix_incorrect_correct(example):
assert [] == solve(example['u'], example['s'], preseed={'A', 'B'})
def test_preseed_contains_all_correct_and_1x_incorrect(example):
result = solve(example['u'], example['s'], preseed={'B', 'D', 'F', 'C'})
assert [] == result
def test_preseed_contains_2x_correct(example):
result = solve(example['u'], example['s'], preseed={'B', 'F'})
assert [{'B', 'D', 'F'}] == result
def test_preseed_ignores_wrong_type(example):
assert [{'B', 'D', 'F'}] == solve(example['u'], example['s'], preseed=[1])
def test_preseed_empty(example):
assert [{'B', 'D', 'F'}] == solve(example['u'], example['s'], preseed={})
def test_returns_set():
assert isinstance(solve(set(), dict()), list)
def test_preseed_multiple_solutions_choose_correct_possibility(example):
example['s']['G'] = {3, 5, 6}
result_d = solve(example['u'], example['s'], limit=1, preseed={'D'})
result_g = solve(example['u'], example['s'], limit=1, preseed={'G'})
assert [{'B', 'D', 'F'}] == result_d
assert [{'B', 'F', 'G'}] == result_g
def test_accept_list_u(trivial):
assert isinstance(solve(list(trivial['u']), trivial['s']), list)
def test_preseed_multiple_solutions_choose_incorrect_possibility(example):
example['s']['G'] = {3, 5, 6}
result = solve(example['u'], example['s'], limit=1, preseed={'C'})
assert [] == result
def test_accept_tuple_u(trivial):
assert isinstance(solve(tuple(trivial['u']), trivial['s']), list)
def test_s_contains_empty_srow(example):
example['s']['G'] = set()
assert [{'B', 'D', 'F'}] == solve(example['u'], example['s'])
def test_example(example):
assert [{'B', 'D', 'F'}] == solve(example['u'], example['s'])
def test_one_each_in_subset():
u = {1, 2, 3}
s = {10: {2}, 20: {1}, 30: {3}}
assert [{10, 20, 30}] == solve(u, s)
def test_count_one_solution(example):
assert 1 == solve(example['u'], example['s'], count=True)
def test_invalid_limit_multiple_solutions(example):
example['s']['G'] = {3, 5, 6}
result = solve(example['u'], example['s'], limit='a')
assert [{'B', 'D', 'F'}, {'B', 'F', 'G'}] == result
def test_count_no_solution(example):
example['s']['D'].remove(6)
example['s']['E'].remove(6)
assert 0 == solve(example['u'], example['s'], count=True)
def test_count_multiple_solutions(example):
example['s']['G'] = {3, 5, 6}
result = solve(example['u'], example['s'], count=True)
assert 2 == result
"""Examples for exactcover."""
from exactcover.exactcover import solve
# Basic usage
u = {1, 2, 3, 4, 5, 6, 7}
s = {
'A': {1, 4, 7},
'B': {1, 4},
'C': {4, 5, 7},
'D': {3, 5, 6},
'E': {2, 3, 6, 7},
'F': {2, 7},
}
result = solve(u, s)
print(result)
# [{'D', 'F', 'B'}]
# An example with multiple solutions.
u = {1, 2, 3, 4, 5, 6, 7}
s = {
'A': {1, 4, 7},
'B': {1, 4},
'C': {4, 5, 7},
'D': {3, 5, 6},
'E': {2, 3, 6, 7},
'F': {2, 7},
'G': {3, 5, 6},
}
result = solve(u, s)
print(result)
# [{'D', 'F', 'B'}, {'G', 'F', 'B'}]
def test_limit1_multiple_solutions(example):
example['s']['G'] = {3, 5, 6}
assert [{'B', 'D', 'F'}] == solve(example['u'], example['s'], limit=1)
