1122 Hamiltonian Cycle （25 分）

1122 Hamiltonian Cycle （25 分）

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 Kwhich is the number of queries, followed by K lines of queries, each in the format:

n V​1​​ V​2​​ ... V​n​​

where n is the number of vertices in the list, and V​i​​'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.

Sample Input:

6 10
6 2
3 4
1 5
2 5
3 1
4 1
1 6
6 3
1 2
4 5
6
7 5 1 4 3 6 2 5
6 5 1 4 3 6 2
9 6 2 1 6 3 4 5 2 6
4 1 2 5 1
7 6 1 3 4 5 2 6
7 6 1 2 5 4 3 1

Sample Output:

YES
NO
NO
NO
YES
NO

题意：判断是否为Hamiltonian Cycle：条件是简单回路（除最后一个结点以外只出现一次），并且相邻两点之间连通。

 /**
 * Copyright(c)
 * All rights reserved.
 * Author : Mered1th
 * Date : 2019-02-28-00.13.48
 * Description : A1122
 */
 #include<cstdio>
 #include<cstring>
 #include<iostream>
 #include<cmath>
 #include<algorithm>
 #include<string>
 #include<unordered_set>
 #include<map>
 #include<vector>
 #include<set>
 using namespace std;
 ;
 ;
 int G[maxn][maxn];
 int n,m,k;
 int main(){
 #ifdef ONLINE_JUDGE
 #else
     freopen("1.txt", "r", stdin);
 #endif
     scanf("%d%d",&n,&m);
     fill(G[],G[]+maxn*maxn,INF);
     int u,v;
     ;i<m;i++){
         scanf("%d%d",&u,&v);
         G[u][v]=G[v][u]=;
     }
     scanf("%d",&k);
     int t,a;
     ;i<k;i++){
         scanf("%d",&t);
         vector<int> temp;
         bool vis[maxn]={false};
         bool flag=true;
         ;j<t;j++){
             scanf("%d",&a);
             temp.push_back(a);
         }
         ]!=temp[temp.size()-]){
             printf("NO\n");
             continue;
         }
         ;x<temp.size()-;x++){
             ]]!= || vis[temp[x]]==true){
                 printf("NO\n");
                 flag=false;
                 break;
             }
             else{
                 vis[temp[x]]=true;
             }
         }
         if(flag==false) continue;
         ;j<n;j++){
             if(vis[j]==false){
                 printf("NO\n");
                 flag=false;
                 break;
             }
         }
         if(flag) printf("YES\n");
     }
     ;
 }