def test_weighted_graph():
g = WeightedGraph()
g.insert_edge("a", {(9, "b"), (6, "c"), (1, "d")})
assert g.get_neighbors("a") == {(9, "b"), (6, "c"), (1, "d")}
assert g.get_neighbors("b") == {(9, "a")}
assert g.get_neighbors("c") == {(6, "a")}
assert g.get_neighbors("d") == {(1, "a")}
assert g.get_weight("a", "b") == 9
assert g.get_weight("a", "c") == 6
assert g.get_weight("a", "d") == 1
def dijkstra(g: WeightedGraph, s: list):
dist = {}
pred = {}
Q = PriorityQueue()
def relax(u, v):
if dist[v] > dist[u] + g.get_weight(u, v):
dist[v] = dist[u] + g.get_weight(u, v)
pred[v] = u
while not Q.empty():
u = Q.get()
s.append(u)
for v in g.get_neighbors(u):
relax(u, v)