最小生成树python

在Python中，可以使用Prim算法或Kruskal算法来实现最小生成树。下面是一个使用Prim算法的示例代码：

import sys

class Graph:
    def __init__(self, vertices):
        self.V = vertices
        self.graph = [[0 for _ in range(vertices)] for _ in range(vertices)]

    def min_key(self, key, mst_set):
        min_val = sys.maxsize
        min_index = -1
        for v in range(self.V):
            if key[v] < min_val and mst_set[v] == False:
                min_val = key[v]
                min_index = v
        return min_index

    def prim_mst(self):
        key = [sys.maxsize] * self.V
        parent = [None] * self.V
        key[0] = 0
        mst_set = [False] * self.V

        parent[0] = -1

        for _ in range(self.V):
            u = self.min_key(key, mst_set)
            mst_set[u] = True

            for v in range(self.V):
                if self.graph[u][v] > 0 and mst_set[v] == False and key[v] > self.graph[u][v]:
                    key[v] = self.graph[u][v]
                    parent[v] = u

        return parent

    def print_mst(self, parent):
        print("Edge \tWeight")
        for i in range(1, self.V):
            print(parent[i], "-", i, "\t", self.graph[i][parent[i]])

# 测试代码
g = Graph(5)
g.graph = [[0, 2, 0, 6, 0],
           [2, 0, 3, 8, 5],
           [0, 3, 0, 0, 7],
           [6, 8, 0, 0, 9],
           [0, 5, 7, 9, 0]]

parent = g.prim_mst()
g.print_mst(parent)

这段代码使用了邻接矩阵来表示图，并实现了Prim算法来找到最小生成树。你可以根据自己的需求调整图的表示方式和权值。