1134. Vertex Cover (25)
時間限制
600 ms
記憶體限制
65536 kB
代碼長度限制
16000 B
判題程式
Standard
作者
CHEN, Yue
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<stdio.h>
const int N = 1e5 + 10;
int n, m, q, x, y;
int a[N], b[N], c[N];
int main(){
scanf("%d%d",&n,&m);
for (int i = 0;i<m;i++) {
scanf("%d%d",&a[i],&b[i]);
}
scanf("%d",&q);
while (q--) {
scanf("%d",&x);
for (int i = 0;i<n;i++) c[i] = 0;
while (x--) scanf("%d",&y),c[y] = 1;
int flag = 1;
for (int i = 0;i<m;i++) {
if(c[a[i]]+c[b[i]]) continue;
flag = 0; break;
}
puts(flag?"Yes":"No");
}
return 0;
}