Codeforces 375 D Tree and Queries

Discription

You have a rooted tree consisting of n vertices. Each vertex of the tree has some color. We will assume that the tree vertices are numbered by integers from 1 to n. Then we represent the color of vertex v as cv. The tree root is a vertex with number 1.

In this problem you need to answer to m queries. Each query is described by two integers vj, kj. The answer to query vj, kj is the number of such colors of vertices x, that the subtree of vertex vj contains at least kj vertices of color x.

You can find the definition of a rooted tree by the following link: http://en.wikipedia.org/wiki/Tree_(graph_theory).

Input

The first line contains two integers n and m (2 ≤ n ≤ 105; 1 ≤ m ≤ 105). The next line contains a sequence of integers c1, c2, ..., cn(1 ≤ ci ≤ 105). The next n - 1 lines contain the edges of the tree. The i-th line contains the numbers ai, bi(1 ≤ ai, bi ≤ nai ≠ bi) — the vertices connected by an edge of the tree.

Next m lines contain the queries. The j-th line contains two integers vj, kj(1 ≤ vj ≤ n; 1 ≤ kj ≤ 105).

Output

Print m integers — the answers to the queries in the order the queries appear in the input.

Example
Input
8 5
1 2 2 3 3 2 3 3
1 2
1 5
2 3
2 4
5 6
5 7
5 8
1 2
1 3
1 4
2 3
5 3
Output
2
2
1
0
1
Input
4 1
1 2 3 4
1 2
2 3
3 4
1 1
Output
4
Note

A subtree of vertex v in a rooted tree with root r is a set of vertices {u : dist(r, v) + dist(v, u) = dist(r, u)}. Where dist(x, y) is the length (in edges) of the shortest path between vertices x and y.

 

 

dfs+莫队,本来挺傻的一个题,结果莫队写错了2333

以前都不是很在意莫队区间端点的移动,但是今天的事情证明了,莫队端点移动要先扩张区间,然后再缩减区间,不然有些题出现了左端点比右端点大的区间会挂掉2333

 

#include
#define ll long long
const int maxn=100005;
using namespace std;
struct ask{
	int l,r,k,bl,num;
	bool operator <(const ask &u)const{
		return bl==u.bl?((bl&1)?ru.r):blq[i].l) le--,add(le);
		while(ri>q[i].r) del(ri),ri--;
		while(le

 

转载于:https://www.cnblogs.com/JYYHH/p/8609136.html

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