# 1122 Hamiltonian Cycle

The “Hamilton cycle problem” is to find a simple cycle that contains every vertex in a graph. Such a cycle is called a “Hamiltonian cycle”.

In this problem, you are supposed to tell if a given cycle is a Hamiltonian cycle.

## Input Specification:

Each input file contains one test case. For each case, the first line contains 2 positive integers N (2<N≤200), the number of vertices, and M, the number of edges in an undirected graph. Then M lines follow, each describes an edge in the format `Vertex1 Vertex2`, where the vertices are numbered from 1 to N. The next line gives a positive integer K which is the number of queries, followed by K lines of queries, each in the format:

n V1 V2 … Vn

where n is the number of vertices in the list, and Vi’s are the vertices on a path.

## Output Specification:

For each query, print in a line `YES` if the path does form a Hamiltonian cycle, or `NO` if not.

# 思路

1. 满足回路，即路径首尾相同
2. 经过所有节点且经过一次
3. 路径必须是连通的，即路径中相邻节点必须有路

# 参考资料

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