读图并输出图的邻接链表，输入两个结点，用广度优先寻找它们之间的最短路径并输出，并判断其是否是树，是否连通，是否有环，有要打印出来环．-interpret drawings and prints of adjacent chain, the importation of two nodes, with breadth between them priority for the shortest path and output, and a judgment whether it is trees,