Submission #890783

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Source Code Expand

#include <iostream>
#include <vector>
#include <cstring>
#include <string>
#include <algorithm>
#include <iomanip>
#include <cmath>
#include <cassert>
using namespace std;



int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int N;
	cin >> N;
	vector<int> a(N);
	for(int i = 0; i < N; i++) {
		cin >> a[i];
		a[i]--;
	}
	int ans = 0;
	for(int i = 0; i < N; i++) {
		if(a[a[i]] == i) ans++;
	}

	cout << ans / 2 << endl;
}

Submission Info

Judge Result