How Many Tables(HDU1213)(入门)

どこでもドア：http://acm.hdu.edu.cn/showproblem.php?pid=1213

N个编号，M个连通
输出有几个集合
CODE:

#include<iostream>#include<cstdio>#include<algorithm>#include<cmath>using namespace std;const int MAX=100005;int ma[MAX];int sum;int Find(int x){    return x==ma[x]? x: ma[x]=Find(ma[x]);}void mix(int x,int y){    x=Find(x);    y=Find(y);    if(x!=y)        ma[y]=x;}int main(){    int t,x,y,n,m;    scanf("%d",&t);    while(t--)    {        sum=0;        scanf("%d%d",&n,&m);        for(int i=1;i<=n;i++)            ma[i]=i;        while(m--)        {            scanf("%d%d",&x,&y);            mix(x,y);        }        for(int i=1;i<=n;i++)            if(ma[i]==i)                sum++;        cout<<sum<<endl;    }    return 0;}