Submission #2075750

---

Source Code Expand

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef pair<LL,LL> P;
const LL mod=1000000007;

int main(){
    int N;
    cin >> N;
    vector<int> v[N];
    for(int i=0;i<N;i++){
        int u;
        cin >> u;
        v[i].push_back(u-1);
    }
    int ans=0;
    for(int i=0;i<N;i++){
        int t=v[i][0];
        if(v[t][0]==i) ans++; 
    }
    cout << ans/2 << endl;
    return 0;
}

Submission Info

Judge Result