CF1899G.Unusual Entertainment
普及/提高-
通过率:0%
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题目描述
A tree is a connected graph without cycles.
A permutation is an array consisting of n distinct integers from 1 to n in any order. For example, [5,1,3,2,4] is a permutation, but [2,1,1] is not a permutation (as 1 appears twice in the array) and [1,3,2,5] is also not a permutation (as n=4 , but 5 is present in the array).
After a failed shoot in the BrMeast video, Alex fell into depression. Even his birthday did not make him happy. However, after receiving a gift from Timofey, Alex's mood suddenly improved. Now he spent days playing with the gifted constructor. Recently, he came up with an unusual entertainment.
Alex builds a tree from his constructor, consisting of n vertices numbered from 1 to n , with the root at vertex 1 . Then he writes down each integer from 1 to n in some order, obtaining a permutation p . After that, Alex comes up with q triples of integers l,r,x . For each triple, he tries to determine if there is at least one descendant of vertex x among the vertices pl,pl+1,…,pr .
A vertex u is a descendant of vertex v if and only if dist(1,v)+dist(v,u)=dist(1,u) , where dist(a,b) is the distance between vertices a and b . In other words, vertex v must be on the path from the root to vertex u .
Alex told Zakhar about this entertainment. Now Alex tells his friend q triples as described above, hoping that Zakhar can check for the presence of a descendant. Zakhar is very sleepy, so he turned to you for help. Help Zakhar answer all of Alex's questions and finally go to sleep.
输入格式
The first line of the input contains a single integer t ( 1≤t≤104 ) — the number of test cases.
The first line of each test case contains two integers n,q ( 1≤n,q≤105 ) — the number of vertices in the tree and the number of questions, respectively.
Each of the next n−1 lines contains two integers ui and vi ( 1≤ui,vi≤n ), indicating that there is an edge between vertices ui and vi (it is guaranteed that the resulting graph is a tree).
The next line contains n integers p1,p2,…,pn ( 1≤pi≤n ) — the permutation p (it is guaranteed that each integer from 1 to n appears exactly once).
Then follow q lines describing Alex's questions. The i -th line contains three integers l,r,x ( 1≤l≤r≤n , 1≤x≤n ), as described in the statement.
It is guaranteed that the sum of n and the sum of q over all test cases do not exceed 105 .
输出格式
For each of Alex's questions, print "Yes" (without quotes) if the described descendant exists, otherwise print "No" (without quotes).
You can output the answer in any case (for example, the strings "yEs", "yes", "Yes", and "YES" will be recognized as a positive answer).
输入输出样例
输入#1
3 3 5 1 2 2 3 1 2 3 1 2 2 1 2 3 2 3 1 1 2 3 2 3 3 10 10 2 6 2 7 2 4 1 7 2 8 10 6 8 5 9 4 3 4 10 2 5 9 1 7 6 4 3 8 8 9 8 7 8 1 7 10 6 4 8 9 5 5 10 7 10 1 9 9 2 9 10 6 6 6 2 10 10 6 1 1 1 1 1 1
输出#1
YES NO YES NO YES NO YES YES YES NO YES YES NO NO NO YES