hdu1213 How many tables 并查集

#include<cstdio>
const int MAXN=1000+50;
int p[MAXN];
int find(int x){
return x!=p[x]?p[x]=find(p[x]):x;
}
void unite(int a,int b){
p[a]=b;
}
int main(){
int n;
while(scanf("%d",&n)!=EOF){
while(n--){
int N,M;
scanf("%d%d",&N,&M);
for(int i=1;i<=N;i++){
p[i]=i;
}
for(int i=0;i<M;i++){
int a,b;
scanf("%d%d",&a,&b);
a=find(a),b=find(b);
if(a!=b)
unite(a,b);
}
int cnt=0;
for(int i=1;i<=N;i++)
if(p[i]==i)
cnt++;
printf("%d\n",cnt);
}
}
return 0;
}