Submission #891384

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Source Code Expand

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

#define PI 4*atan(1)
#define INF 1e8

int dx[4] = {1,0,-1,0};
int dy[4] = {0,1,0,-1};

int main(){
  int N;
  cin >> N;
  vector<int> a(N), tmp(N, -1);
  for(int i = 0; i < N; i++){
    cin >> a[i];
    tmp[i] = a[i];
  }
  int cnt = 0;
  for(int i = 0; i < N; i++){
    if(i != -1 && i == tmp[a[i]]){
      cnt++;
      tmp[i] = -1;
      tmp[a[i]] = -1;
    }
  }
  cout << cnt << endl;
}

Submission Info

Judge Result