Submission #891179

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Source Code Expand

#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <iomanip>
#include <algorithm>
#include <queue>
#include <cmath>
#include <numeric>
#include <functional>
#include <cstring>
#include <set>
using namespace std;

typedef long long ll;
#define MAX 1e9+7
#define rep(i,n) for(int i=0;i<n;i++)

int main()
{
	int n; cin >> n;
	vector<int> a(n);
	rep(i, n) {
		cin >> a[i];
	}
	int cnt=0;
	rep(i, n) {
		if (a[a[i] - 1] == i + 1)cnt++;
	}

	cout << cnt / 2 << endl;

	return 0;
}

Submission Info

Judge Result