def shortest_path(source, target):
solution = []
# Initialize frontier to just the starting position
start = Node(parent=None, star_id=source, movie_id=None)
queue = Queue()
queue.add(start)
# Initialize an empty explored set
explored = set()
while True:
node = queue.remove()
if node.star_id == target:
while node.parent is not None and node.movie_id is not None:
solution.append([node.movie_id, node.star_id])
node = node.parent
solution.reverse()
return solution
explored.add(node.movie_id)
for actor in neighbors_for_person(node.star_id):
if (actor[0] not in explored):
child = Node(star_id=actor[1], movie_id=actor[0], parent=node)
queue.add(child)
