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.

10 118 76 84 58 48 11 21 49 89 11 02 454 0 3 8 46 6 1 7 5 4 93 1 8 42 2 87 9 8 7 6 5 4 2

NoYesYesNoNo

#include 
     
      #include 
      
       using namespace std;int main(){    int n, m, a, b;    cin >> n >> m;    vector
       
         nv[n];        for (int i = 0; i < m; i++) {        cin >> a >> b;        nv[a].push_back(i);        nv[b].push_back(i);    }        int k, p, t;    cin >> k;    for (int i = 0; i < k; i++) {        bool ans[m];        fill(ans, ans+m, false);        cin >> p;                for (int j = 0; j < p; j++) {            cin >> t;            for (int k = 0; k < nv[t].size(); k++) {                ans[nv[t][k]] = true;            }        }                bool flag = true;        for (int j = 0; j < m; j++) {            if (!ans[j]) {                flag = false;                break;            }        }                if (flag) {            cout << "Yes\n";        }else{            cout << "No\n";        }    }        return 0;}