最小生成树问题

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，是一个网的最小生成树问题。

（1）利用克鲁斯卡尔算法求网的最小生成树。

（2）实现教科书6.5节中定义的抽象树类型 MFSet。以此表示构造生成树过程中的连通分量。

（3）以文本形式输出生成树中各条边以及他们的权值。

-minimum spanning tree problem to the n-city building communications networks needed to put up only n-1 lines can be. How the lowest economic cost of building the communications network, the network is a minimum spanning tree problem. (1) using Kelushikaer network algorithm for the minimum spanning tree. (2) to achieve 6.5 textbook definition of the abstract tree types MFSet. Spanning Tree Construction said this process of connectivity components. (3) the form of text output spanning trees and the edge of their weights.