1213 并查集模板（计算集合数）

/* ***********************************************
Author        :PeterBishop
Created Time  :Sat 16 Feb 2019 21:23:18 CST
File Name     :t.cpp
Origin        :H D O J  1213
************************************************ */

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstdlib>
#include <vector>
#include <queue>
#include <set>
#include <map>

using namespace std;
struct node{
    int p;
}S[1002];
void init(int n){
    for(int i=1;i<=n;i++)
        S[i].p=i;
}
int find(int x){
    return x==S[x].p?x:find(S[x].p);
}
void join(node a,node b){
    int r1=find(a.p);
    int r2=find(b.p);
    if(r1!=r2)
        S[r1].p=r2;
}

int main()
{
    freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);
    int T,N,m;
    while(cin>>T){
        while(T--){
            cin>>N>>m;
            init(N);
            for(int i=0;i<m;i++){
                int a,b;
                cin>>a>>b;
                join(S[a],S[b]);
            }
            int ans=0;
            for(int i=1;i<=N;i++)
                if(S[i].p==i)
                    ans++;
            cout<<ans<<endl;
        }
    }
    return 0;
}