PAT 甲级 1134. Vertex Cover (25)

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 104), 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 (<= 100) is given, which is the number of queries. Then K lines of queries follow, each in the format:

Nv v[1] v[2] … v[Nv]

where Nv 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

#include<iostream>
#include<vector>

using namespace std;
bool book[10010];
struct edge {
int a;
int b;
};
int main()
{
int n, m;
cin >> n >> m;
vector<edge> e(m);
for (int i = 0;i < m;i++) {
cin >> e[i].a >> e[i].b;
}
int k;
cin >> k;
for (int i = 0;i < k;i++) {
int num,temp;
cin >> num;
bool book[10010] = { false };
for (int j = 0;j < num;j++) {
cin >> temp;
book[temp] = true;
}
bool flag = true;
for (int j = 0;j < m;j++) {
if (book[e[j].a] || book[e[j].b])
{
continue;
}
else {
flag = false;
break;
}
}
if (flag)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
cin >> n;
return 0;
}