Codeforces Round 221 (Div. 1)
D
Tree and Queries
Codeforces
2400
原题
← CE →
翻译中…

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 $*c*_{*v*}$. The tree root is a vertex with number 1.

翻译中…

In this problem you need to answer to $*m*$ queries. Each query is described by two integers $*v*_{*j*}, *k*_{*j*}$. The answer to query $*v*_{*j*}, *k*_{*j*}$ is the number of such colors of vertices $*x*$, that the subtree of vertex $*v*_{*j*}$ contains at least $*k*_{*j*}$ vertices of color $*x*$.

翻译中…

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

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Input

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The first line contains two integers $*n*$ and $*m*$ $(2 ≤ *n* ≤ 10^{5}; 1 ≤ *m* ≤ 10^{5})$. The next line contains a sequence of integers $*c*_{1}, *c*_{2}, ..., *c*_{*n*}$ $(1 ≤ *c*_{*i*} ≤ 10^{5})$. The next $*n* - 1$ lines contain the edges of the tree. The $*i*$-th line contains the numbers $*a*_{*i*}, *b*_{*i*}$ $(1 ≤ *a*_{*i*}, *b*_{*i*} ≤ *n*; *a*_{*i*} ≠ *b*_{*i*})$ — the vertices connected by an edge of the tree.

翻译中…

Next $*m*$ lines contain the queries. The $*j*$-th line contains two integers $*v*_{*j*}, *k*_{*j*}$ $(1 ≤ *v*_{*j*} ≤ *n*; 1 ≤ *k*_{*j*} ≤ 10^{5})$.

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Output

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

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Note

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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 $*y*$.

翻译中…

样例

Input #1
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 #1
2
2
1
0
1
InputCopy OutputCopy
Input #2
4 1
1 2 3 4
1 2
2 3
3 4
1 1
Output #2
4
InputCopy OutputCopy
题目信息
题号
375D
时间限制
1 s
内存限制
256 MB
标签
数据结构
DFS 及类似
树

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。