Submission #891693

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;

int main(void){
  int n;
  vector<int> v;
  cin >> n;
  for(int i = 0;i < n;++i){
    int a;
    cin >> a;
    --a;
    v.push_back(a);
  }
  int res = 0;
  for(int i = 0;i < n;++i){
    if(v[v[i]] == i)++res;
  }
  cout << res/2 << endl;
  return 0;
}

Submission Info

Judge Result