最近公共祖先问题 问题描述：给定一棵树，设计一个算法对于给定的两个结点返回他们的最近公共祖先 实验任务：对于给定的树和树中的结点对，输出最近公共祖先-Recently, the issue of public issue of ancestral Descr iption: given a tree, to design an algorithm for a given node of the two return to their ancestors in recent experim