Submission #7086620

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Source Code Expand

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

int main() {
  int N;
  cin >> N;
  
  vector<int> usagi(N);
  for( int i = 0; i < N; i++ ){
    cin >> usagi.at(i);
  }
  
  int count = 0;
  for( int i = 0; i < N; i++ ){
    if( usagi.at(usagi.at(i)-1) == i+1 ){
      count++;
    }
  }
  cout << count / 2 << endl;
  
}

Submission Info

Judge Result