用无向图表示n个城市之间的交通网络建设规划，顶点表示城市，边上的权表示该线路的造价，试设计一个方案，使得这个交通网的总造价最小，即求最小生成树问题。-Undirected graph with n cities that traffic between the network construction plan, the vertices represent the city, right next to that the cost of the line, try to design a pr