def djikstra(start, neighbor_func, distance_func, goal_pred):
visited = set()
parents = {start: None}
distances = {start: 0}
queue = PQ()
queue.add_task(start, distances[start])
while not queue.empty():
current = queue.pop_task()
for neighbor in neighbor_func(current):
if neighbor in visited:
continue
tentative_distance = distances[current] + distance_func(
current, neighbor)
if neighbor not in distances:
queue.add_task(neighbor, tentative_distance)
distances[neighbor] = tentative_distance
parents[neighbor] = current
elif tentative_distance < distances[neighbor]:
queue.update_task(neighbor, tentative_distance)
distances[neighbor] = tentative_distance
parents[neighbor] = current
visited.add(current)
if goal_pred(current):
return {
"distance": distances[current],
"path": reconstruct_path(current, parents),
"parents": parents
}
return {"distance": float("inf"), "path": None, "parents": parents}
