用python写dijkstra求最短路径代码

好的，以下是用Python实现Dijkstra算法求最短路径的代码：

import heapq

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

其中，参数 `graph` 表示的是用字典表示的图，例如：{'A': {'B': 1, 'C': 4}, 'B': {'A': 1, 'C': 2}, 'C': {'A': 4, 'B': 2, 'D': 3}, 'D': {'C': 3}}。参数 `start` 表示起点。函数返回值是一个字典，表示从起点到每个节点的最短路径长度。

希望能够帮到你！