poj 2524 求连通分量（并查集模板题）

求连通分量

Sample Input

10 9
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
10 4
2 3
4 5
4 8
5 8
0 0
Sample Output

Case 1: 1
Case 2: 7

 # include <iostream>
 # include <cstdio>
 # include <cstring>
 # include <algorithm>
 # include <cmath>
 # include <queue>
 # define LL long long
 using namespace std ;

 const int MAXN = ;
 int F[MAXN];
 int num[MAXN] ;

 int find(int x)//找x的祖先结点
 {
     if(F[x]==x) return x;
     return F[x]=find(F[x]);
 }
 void bing(int u,int v) //按秩合并
 {
     int x = find(u);
     int y = find(v);
     if(x == y)
         return ;
     if(num[x] >= num[y])
     {
         F[y] = x;
         num[x] += num[y];
     }
     else
     {
         F[x] = y;
         num[y] += num[x];
     }
 }
 int main()
 {
     //freopen("in.txt","r",stdin) ;
     int n , m ;
     int Case =  ;
     while(scanf("%d %d", &n , &m) != EOF)
     {
          Case++ ;
          if (n ==  && m == )
              break ;

          int i ;
          for(i =  ; i <= n ; i++)
          {
              F[i] = i ;
              num[i] =  ;
          }
         int u , v ;
         while(m--)
         {
             scanf("%d %d" , &u , &v) ;
             bing(u , v) ;

         }
         int res =  ;
         for(i =  ; i <= n ; i++)
             if (F[i] == i)
                res++ ;
         printf("Case %d: %d\n" , Case , res) ;
     }
     return ;
 }