Submission #890892

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Source Code Expand

#include <math.h>
#include <stdio.h>
#include <string.h>
#include <vector>
#include <string>
#include <queue>
#include <map>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <sstream>
#include <set>
using namespace std;

int main()
{
  int n;
  cin >> n;
  map<int, int> M;
  for (int i=0; i<n; i++) {
    int c;
    cin >> c;
    M[i+1] = c;
  }
  int res = 0;
  for (int i=0; i<n; i++)
    if (M[M[i+1]] == i+1) res ++;
  cout << res / 2 << endl;
}

Submission Info

Judge Result