Cymbals的博客

There are n houses in the village and some bidirectional roads connecting them. Every day peole always like to ask like this “How far is it if I want to go from house A to house B”? Usually it hard to...

两道题都是树上异或最大值的问题，这一类问题都是可持久化01字典树的模板题，不过需要一些树论知识来处理一下。 HDU - 4757： 求树上两点路径间的异或最大值。 显而易见，两点路径就是个lca。 对每一个节点，以其父亲为last版本，新建可持久化字典树即可。 最后用(sz[next[now][!d]] + sz[next[now2][!d]]) - (2 * sz[next[now3][!d]]...

You are given a tree with N nodes. The tree nodes are numbered from 1 to N. Each node has an integer weight. We will ask you to perform the following operation: u v k : ask for the kth minimum weight ...