CF1304E.1-Trees and Queries
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题目描述
Gildong was hiking a mountain, walking by millions of trees. Inspired by them, he suddenly came up with an interesting idea for trees in data structures: What if we add another edge in a tree?
Then he found that such tree-like graphs are called 1-trees. Since Gildong was bored of solving too many tree problems, he wanted to see if similar techniques in trees can be used in 1-trees as well. Instead of solving it by himself, he's going to test you by providing queries on 1-trees.
First, he'll provide you a tree (not 1-tree) with n vertices, then he will ask you q queries. Each query contains 5 integers: x , y , a , b , and k . This means you're asked to determine if there exists a path from vertex a to b that contains exactly k edges after adding a bidirectional edge between vertices x and y . A path can contain the same vertices and same edges multiple times. All queries are independent of each other; i.e. the added edge in a query is removed in the next query.
输入格式
The first line contains an integer n ( 3≤n≤105 ), the number of vertices of the tree.
Next n−1 lines contain two integers u and v ( 1≤u,v≤n , u=v ) each, which means there is an edge between vertex u and v . All edges are bidirectional and distinct.
Next line contains an integer q ( 1≤q≤105 ), the number of queries Gildong wants to ask.
Next q lines contain five integers x , y , a , b , and k each ( 1≤x,y,a,b≤n , x=y , 1≤k≤109 ) – the integers explained in the description. It is guaranteed that the edge between x and y does not exist in the original tree.
输出格式
For each query, print "YES" if there exists a path that contains exactly k edges from vertex a to b after adding an edge between vertices x and y . Otherwise, print "NO".
You can print each letter in any case (upper or lower).
输入输出样例
输入#1
5 1 2 2 3 3 4 4 5 5 1 3 1 2 2 1 4 1 3 2 1 4 1 3 3 4 2 3 3 9 5 2 3 3 9
输出#1
YES YES NO YES NO
说明/提示
The image below describes the tree (circles and solid lines) and the added edges for each query (dotted lines).
Possible paths for the queries with "YES" answers are:
- 1 -st query: 1 – 3 – 2
- 2 -nd query: 1 – 2 – 3
- 4 -th query: 3 – 4 – 2 – 3 – 4 – 2 – 3 – 4 – 2 – 3