用python写一个dijkstra算法

好的，以下是用 Python 写的 Dijkstra 算法样例代码：

import heapq

def dijkstra(graph, start):
    distances = {node: float('inf') for node in graph}
    distances[start] = 0
    
    queue = [(0, start)]
    while queue:
        current_distance, current_node = heapq.heappop(queue)
        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(queue, (distance, neighbor))
    
    return distances

其中，graph 是一个字典，存储了图中每个节点和它们的邻居及其权重信息，start 是从哪个节点开始计算最短路径。函数返回一个字典，包含从 start 节点出发到图中每个节点的最短路径距离。

希望这个算法能帮到你！