摘要：题目大意：一棵树，然后m个询问，每个询问有k个点，然后判断是否有一条路，要求这k个点要么在这条路上，要么和这条路相距为1. 题解：刚开始的思路是这样的，这条路的终点肯定是深度最深的那个点，然后用BFS找到从1到终点的路线，然后在对路径上的点和与路径直接相连的点进行判断，看这k个点是否都在其中，然后就 阅读全文

摘要：A rooted tree is a well-known data structure in computer science and engineering. An example is shown below: In the figure, each node is labeled with 阅读全文

摘要：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 阅读全文

摘要：Language: Default Closest Common Ancestors Time Limit: 2000MS Memory Limit: 10000K Total Submissions: 24653 Accepted: 7648 Description Write a program 阅读全文

摘要：例题：http://poj.org/problem?id=1986 POJ1986 Distance Queries Language: Default Distance Queries Time Limit: 2000MS Memory Limit: 30000K Total Submission 阅读全文

摘要：https://www.luogu.org/problemnew/solution/P3379 LCA叫做最短公共祖先，用来求距离树上两个节点最近的公共点； 常用倍增算法： 阅读全文