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;}