def shortest_path(source, target):
"""
Returns the shortest list of (movie_id, person_id) pairs
that connect the source to the target.
If no possible path, returns None.
"""
frontier = QueueFrontier()
node = Node(source, None, None)
frontier.add(node)
nodes_explored = []
edges = dict()
print("Calculating...")
while True:
if frontier.empty():
graph = Graph(edges, [])
graph.draw_graph("my_graph.png")
return None
node = frontier.remove()
node_person_name = people[node.get_person_id()]["name"]
if node.get_person_id() == target:
path = []
path_name_labels = [people[source]["name"]]
while node.get_parent() is not None:
path.append([node.get_movie_id(), node.get_person_id()])
path_name_labels.append(people[node.get_person_id()]["name"])
node = node.get_parent()
path.reverse()
graph = Graph(edges, path_name_labels)
graph.draw_graph("output_graph.png")
return path
else:
nodes_explored.append(node.get_person_id())
for movie_id, person_id in neighbors_for_person(node.get_person_id()):
child = Node(person_id, node, movie_id)
child_person_name = people[child.get_person_id()]["name"]
movie_name = movies[child.get_movie_id()]["title"]
if(node_person_name != child_person_name):
edges[(node_person_name, child_person_name)] = movie_name
if not frontier.contains_state(person_id) and person_id not in nodes_explored:
frontier.add(child)
