1函数prim的算法python

def prim(graph):
    # 初始化最小生成树和已访问节点集合
    mst = []
    visited = set()

    # 选择初始节点
    start_node = list(graph.keys())[0]
    visited.add(start_node)

    while len(visited) < len(graph):
        min_edge = None
        min_weight = float('inf')

        # 遍历已访问节点集合中的节点
        for node in visited:
            # 遍历与当前节点相连的边
            for neighbor, weight in graph[node].items():
                # 如果边的另一端节点未访问且权重更小，则更新最小边
                if neighbor not in visited and weight < min_weight:
                    min_edge = (node, neighbor)
                    min_weight = weight

        # 将最小边加入最小生成树，并将边的另一端节点加入已访问节点集合
        mst.append(min_edge)
        visited.add(min_edge[1])

    return mst