def test_sanity(self):
"""
Sanity Test
This is a simple sanity check for your function;
passing is not a guarantee of correctness.
"""
g1 = Graph(is_directed=True)
g1.add_edge('a', 'b', capacity=16, flow=12)
g1.add_edge('a', 'c', capacity=13, flow=11)
g1.add_edge('b', 'd', capacity=12, flow=12)
g1.add_edge('c', 'b', capacity=4, flow=0)
g1.add_edge('c', 'e', capacity=14, flow=11)
g1.add_edge('d', 'c', capacity=9, flow=0)
g1.add_edge('d', 'f', capacity=20, flow=19)
g1.add_edge('e', 'd', capacity=7, flow=7)
g1.add_edge('e', 'f', capacity=4, flow=4)
self.assertFalse(AugmentingTest.augmenting(g1, 'a', 'f'))
g2 = g1.copy()
g2.set_flow('b', 'd', 11)
self.assertTrue(AugmentingTest.augmenting(g2, 'a', 'f'))
g3 = Graph(is_directed=True)
g3.add_edge('a', 'b', capacity=1, flow=0)
self.assertTrue(AugmentingTest.augmenting(g3, 'a', 'b'))
g4 = Graph(is_directed=True)
g4.add_edge('a', 'b', capacity=0, flow=0)
self.assertFalse(AugmentingTest.augmenting(g4, 'a', 'b'))
def sensitive(G: Graph, s: str, t: str) -> Tuple[str, str]:
"""
Sig: Graph G(V,E), str, str -> Tuple[str, str]
Pre:
Post:
Ex: sensitive(g1, 'a', 'f') = ('b', 'd')
"""
R = G.copy()
nodes = set()
dfs_residual(G, R, s, nodes)
reachable = set()
dfs_find_reachable(R, s, reachable)
for (u, v) in G.edges:
if u in reachable and v not in reachable:
return (u, v)
def test_extended_sanity(self):
"""
sanity test for returned augmenting path
This is a simple sanity check for your function;
passing is not a guarantee of correctness.
"""
g1 = Graph(is_directed=True)
g1.add_edge('a', 'b', capacity=16, flow=12)
g1.add_edge('a', 'c', capacity=13, flow=11)
g1.add_edge('b', 'd', capacity=12, flow=12)
g1.add_edge('c', 'b', capacity=4, flow=0)
g1.add_edge('c', 'e', capacity=14, flow=11)
g1.add_edge('d', 'c', capacity=9, flow=0)
g1.add_edge('d', 'f', capacity=20, flow=19)
g1.add_edge('e', 'd', capacity=7, flow=7)
g1.add_edge('e', 'f', capacity=4, flow=4)
path_exists, path = AugmentingTest.augmenting_extended(g1, 'a', 'f')
self.assertFalse(path_exists)
self.assertListEqual(path, [])
g2 = g1.copy()
g2.set_flow('b', 'd', 11)
path_exists, path = AugmentingTest.augmenting_extended(g2, 'a', 'f')
self.assertTrue(path_exists)
self.assertIsAugmentingPath(g2, 'a', 'f', path)
g3 = Graph(is_directed=True)
g3.add_edge('a', 'b', capacity=1, flow=0)
path_exists, path = AugmentingTest.augmenting_extended(g3, 'a', 'b')
self.assertTrue(path_exists)
self.assertIsAugmentingPath(g2, 'a', 'b', path)
g4 = Graph(is_directed=True)
g4.add_edge('a', 'b', capacity=0, flow=0)
path_exists, path = AugmentingTest.augmenting_extended(g4, 'a', 'b')
self.assertFalse(path_exists)
self.assertListEqual(path, [])