帮我用Python写个二叉堆优化的戴克斯特拉算法

好的，以下是使用 Python 实现的带二叉堆优化的 Dijkstra 算法的代码：

import heapq
from collections import defaultdict

def dijkstra(graph, start):
    distances = {vertex: float('infinity') for vertex in graph}
    distances[start] = 0
    heap = [(0, start)]
    while heap:
        (current_distance, current_vertex) = heapq.heappop(heap)
        if current_distance > distances[current_vertex]:
            continue
        for neighbor, weight in graph[current_vertex].items():
            distance = current_distance + weight
            if distance < distances[neighbor]:
                distances[neighbor] = distance
                heapq.heappush(heap, (distance, neighbor))
    return distances

if __name__ == "__main__":
    graph = defaultdict(dict)
    graph['A']['B'] = 1
    graph['A']['C'] = 4
    graph['B']['C'] = 2
    graph['B']['D'] = 5
    graph['C']['D'] = 1
    print(dijkstra(graph, 'A'))

希望对您有所帮助！