Submission #890902

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Source Code Expand

#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

int main() {
  int n;
  int a[100000];
  int x = 0;
  std::cin >> n;
  for (int ni = 0; ni < n; ++ni) {
    std::cin >> a[ni];
  }
  for (int ni = 0; ni < n; ++ni) {
    if (a[a[ni] - 1] == ni + 1) {
      ++x;
    }
  }
  std::cout << x / 2 << std::endl;
  return 0;
}

Submission Info

Judge Result