管道铺设施工的最佳方案问题（需要在某个城市n个居民小区之间铺设煤气管道，则在这n个居民小区之间只需要铺设n-1条管道即可。假设任意两个小区之间都可以铺设管道，但由于地理环境不同，所需要的费用也不尽相同。选择最优的方案能使总投资尽可能小，这个问题即为求无向网的最小生成树。）本程序即是解决上述问题的，本人自己所写。-The best solution to pipeline construction issues (need a residential area of ​ ​ the city between the n laying gas pipelines, in the residential area between the n n-1 requires only laying the pipeline can be. Assumption of any two cells Rooms are laying pipes, but due to the geographical environment is different, the required fees are not the same. Choose the best solution to make a total investment of as little as possible, the problem is the undirected minimum spanning tree network.) This program that is, to solve these problems, I have written yourself.