hdu1856 More is better 基础并查集

 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 #include <cstdlib>
 using namespace std;

 #define MAXN  100005
 int fa[MAXN];    //父节点
 int vis[MAXN];
 int Min = 0xffffff;
 int Max = ;

 void init()
 {
     for (int i = ; i < MAXN; i++)
     {
         fa[i] = i;
     }
 }

 int find(int x)
 {
     if (x == fa[x])
         return x;
     else
         return fa[x] = find(fa[x]);
 }

 void set_union(int a, int b)
 {
     int a1 = find(a);
     int b1 = find(b);

     if (a1 == b1)
         return;
     else
     {
         if (a1 < b1)
             fa[b1] = a1;
         else
             fa[a1] = b1;
     }
 }

 int main()
 {
     int n;
     while (~scanf("%d",&n))
     {
         init();
         for (int i = ; i < n; i++)
         {
             int a, b;
             scanf("%d %d", &a, &b);

             Min = min(Min, min(a, b));
             Max = max(Max, max(a, b));

             set_union(a, b);
         }

         int ans = ;
         memset(vis, , sizeof(vis));
         for (int i = Min; i <= Max; i++)
         {
             vis[find(i)]++;
             if (ans < vis[find(i)])
                 ans = vis[find(i)];
         }
         printf("%d\n", ans);
     }
     //system("pause");
     return ;
 }