1134 Vertex Cover

Statement

Metadata

作者: CHEN, Yue
单位: 浙江大学
代码长度限制: 16 KB
时间限制: 600 ms
内存限制: 64 MB

A vertex cover of a graph is a set of vertices such that each edge of the graph is incident to at least one vertex of the set. Now given a graph with several vertex sets, you are supposed to tell if each of them is a vertex cover or not.

Input Specification

Each input file contains one test case. For each case, the first line gives two positive integers $N$ and $M$ (both no more than $10^4$ ), being the total numbers of vertices and the edges, respectively. Then $M$ lines follow, each describes an edge by giving the indices (from 0 to $N-1$ ) of the two ends of the edge.

After the graph, a positive integer $K$ ( $\le$ 100) is given, which is the number of queries. Then $K$ lines of queries follow, each in the format:

$N_v$ $v[1]$ $v[2] \cdots v[N_v]$

where $N_v$ is the number of vertices in the set, and $v[i]$ 's are the indices of the vertices.

Output Specification

For each query, print in a line Yes if the set is a vertex cover, or No if not.

Sample Input

10 11
8 7
6 8
4 5
8 4
8 1
1 2
1 4
9 8
9 1
1 0
2 4
5
4 0 3 8 4
6 6 1 7 5 4 9
3 1 8 4
2 2 8
7 9 8 7 6 5 4 2

Sample Output

No
Yes
Yes
No
No

Last update: May 4, 2022