用C写的源程序功能分别是1.用DFS算法判断有向图中是否有环2.从文件中读图，用邻接链表保存信息，寻找两个结点vi,vj间的最短路径-written in C source is a function respectively. DFS algorithm used to determine whether there are plans Central 2. Interpret drawings from the file, use the adjacent Chain preservatio