最小生成树的数据结构解法，若要在n个城市之间建设通信网络，只需要架设n－1条线路即可。如何以最低的经济代价建设这个通信网-Minimum spanning tree method of data structure, to cities in the n-building communications between the network only need to set up n-1 lines to. How to minimize the economic cost of building the communications network