題目：

How Many Tables

25 31 22 34 55 12 5 Sample Output
24 AuthorIgnatius.L Source杭電ACM省賽集訓隊選拔賽之熱身賽 RecommendEddy   |   We have carefully selected several similar problems for you:  1856 1325 1198 1863 1102  Statistic | Submit | Discuss | Note思路：
簡單并查集，不多說~
代碼：
#include <cstdio>#include <cstring>#include <cstdlib>#include <cmath>#include <string>#include <iostream>#include <stack>#include <queue>#include <vector>#include <algorithm>#define mem(a,b) memset(a,b,sizeof(a))#define N 1000+20#define M 30000+20#define MOD 1000000000+7#define inf 0x3f3f3f3fusing namespace std;int n,m;int pre[N];void init(){    for(int i=1; i<=n; i++)        pre[i]=i;}int find(int x){    if(x==pre[x])        return x;    else    {        pre[x]=find(pre[x]);        return pre[x];    }}void mix(int x,int y){    int fx=find(x);    int fy=find(y);    if(fx!=fy)        pre[fy]=pre[x];}int main(){    int t;    scanf("%d",&t);    while(t--)    {        scanf("%d%d",&n,&m);        init();        int a,b;        for(int i=1; i<=m; i++)        {            scanf("%d%d",&a,&b);            mix(a,b);        }        int sum=0;        for(int i=1; i<=n; i++)            if(pre[i]==i)                sum++;        printf("%d/n",sum);    }    return 0;}