并查集

c.

/*
并查集模板
*/
#include<iostream>
#include<stdio.h>
#include<string.h>
using namespace std;

#define MAXN 1024

int fa[MAXN];

int set_find(int d){
    if(fa[d]<0)return d;
    return fa[d]=set_find(fa[d]);
}

void set_join(int x,int y){
    x=set_find(x);
    y=set_find(y);
    if(x!=y)fa[x]=y;
}

int main(){
    int n,m;//点数，边数
    int x,y,i,sum;
    printf("输入点数、边数：");
    while(~scanf("%d%d",&n,&m)){
        memset(fa,-1,sizeof(fa));
        printf("输入边：\n");
        while(m--){
            scanf("%d%d",&x,&y);
            set_join(x,y);
        }
        sum=0;
        for(i=1;i<=n;++i)
            if(fa[i]==-1)++sum;
        printf("集合个数：%d\n",sum);
        printf("输入点数、边数：");
    }
    return 0;
}