POJ 2524 (简单并查集) Ubiquitous Religions

题意：有编号为1到n的学生，然后有m组调查，每组调查中有a和b，表示该两个学生有同样的宗教信仰，问最多有多少种不同的宗教信仰

简单并查集

 //#define LOCAL
 #include <iostream>
 #include <cstdio>
 #include <cstring>
 using namespace std;

 const int maxn =  + ;
 int parent[maxn], n, m;

 int GetParent(int x)
 {
     return parent[x] == x ? x : parent[x] = GetParent(parent[x]);
 }

 void Init(void)
 {
     for(int i = ; i <= n; ++i)
         parent[i] = i;
 }

 int main(void)
 {
     #ifdef LOCAL
         freopen("2524in.txt", "r", stdin);
     #endif

     int kase = ;
     while(scanf("%d%d", &n, &m) ==  && (m + n))
     {
         Init();
         for(int i = ; i < m; ++i)
         {
             int a, b;
             scanf("%d%d", &a, &b);
             int pa = GetParent(a);
             int pb = GetParent(b);
             if(pa != pb)
                 parent[pa] = pb;
         }
         int sum = ;
         for(int i = ; i <= n; ++i)
             if(parent[i] == i)
                 ++sum;
         printf("Case %d: %d\n", ++kase, sum);
     }
     return ;
 }

代码君