Submission #891767

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Source Code Expand

#include <iostream>
#include <vector>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)

int main()
{
	int n;

	cin >> n;

	vector<int> rabbits(n);

	rep(i, n) {
		cin >> rabbits[i];
		rabbits[i]--;
	}

	int ans = 0;

	rep(i, n) {
		if (rabbits[rabbits[i]] == i) {
			ans++;
		}
	}

	cout << ans / 2 << endl;

	return 0;
}

Submission Info

Judge Result