题意：就是判断这个图是不是一个欧拉回路的一个题，

思路：我觉得这个题可以用并查集判环加上判断每个点的度就行了

1 #include 
     
       2 #include 
      
        3 #include 
       
         4 using namespace std; 5 int graph[1005]; 6 int belg[1005]; 7  8  9 int Find(int x)10 {11     int _x=x,_b;12     while( _x != belg[ _x ] )13         _x = belg[ _x ];14     while( x != belg[ x ] )15     {16         _b = belg[ x ];17         belg[ x ] = _x;18         x = _b;19     }20     return _x;21 }22 23 void unio(int x,int y)24 {25     int root1 = Find(x);26     int root2 = Find(y);27     if( root1 != root2 ) belg[root2] = root1;28 }29 30 int main()31 {32     int n,m,a,b;33     while(scanf("%d",&n)&&n)34     {35         int falg = 1,mark;36         scanf("%d",&m);37         memset(graph,false,sizeof(graph));38         for(int i = 1 ; i <= n ; i++)39             belg[i] = i;40         for(int i = 1 ; i <= m ; i++ )41         {42             scanf("%d%d",&a,&b);43             unio(a,b);44             graph[a]++;45             graph[b]++;46         }47         mark  = belg[1];48         for(int i = 1 ; i <= n ; i++)49         {50             if(belg[i]!=mark||(graph[i]&1)) {51                 falg = 0;52                 break;53             }54         }55         if(falg) printf("1\n");56         else printf("0\n");57     }58 }