求助45pts

#include<iostream>
#include<algorithm>
using namespace std;

int f[1000010],broken,havechild[1000010],n;
int comp(int a,int b){return a>b;}

int find(int x){
    if(f[x] == x) return x;
    else return f[x] = find(f[x]);
}

void connect(int x,int y){
    int fx = find(x),fy = find(y);
    if(fx != fy){
        f[y]=x;find(y);
    }
}

int main(){
    ios::sync_with_stdio(0);
    cin>>n;int x;
    for(int i = 1;i <= n;i++)f[i]=i;
    for(int i = 1;i <= n;i++){
        cin>>x;
        connect(x,i);
    }
   
    for(int i = 1;i <= n;i++) havechild[f[i]]++;
    sort(havechild+1,havechild+1+n,comp);int ans=0;
   
    while(broken!=n){
        ans++;broken+=(havechild[ans]);
    }
    cout<<ans<<endl;
    return 0;
}