hdu 1856 求集合里元素的个数 输出最大的个数是多少

求集合里元素的个数 输出最大的个数是多少

Sample Input
4
1 2
3 4
5 6
1 6
4
1 2
3 4
5 6
7 8

Sample Output
4
2

 # 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 ;
     while(scanf("%d",&n) != EOF)
     {
          if (n == )
          {
              printf("1\n") ;
              continue ;
          }
          int i ;
          for(i =  ; i <= MAXN ; i++)
          {
              F[i] = i ;
              num[i] =  ;
          }
         int u , v , t =  ;
         for(i =  ; i <= n ; i++)
         {
             scanf("%d %d" , &u , &v) ;
             bing(u,v) ;
             t = max(t , max(u , v)) ;
         }
         int Max =  ;
         for(i =  ; i <= t ; i++)
             if (num[i] > Max)
                Max = num[i] ;
         printf("%d\n" , Max) ;

     }
     return ;
 }