02 2020 档案
摘要:LCA(least common ancestors)最近公共祖先 指的就是对于一棵有根树,若结点z既是x的祖先,也是y的祖先(不要告诉我你不知道什么是祖先),那么z就是结点x和y的最近公共祖先。 定义到此。 那么怎么求LCA? 对于朴素思想,就是我要一步一步往上爬。。一步一步走。先把结点x和y整到
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摘要:F. Three Paths on a Tree Description You are given an unweighted tree with nn vertices. Recall that a tree is a connected undirected graph without cyc
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