丁字路口、十字路口两种有代表性的情况讨论如何划分节点及设置路径，其他情况可以根据这两种情况的设置原则来灵活设定。-Dingzi junction, a crossroads of two representative to discuss the situation and how the node set up trails Under other circumstances can be both cases, the principle of setting up a flexible s