Submission #891690

---

Source Code Expand

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <cstring>
#include <sstream>
#include <map>
#include <set>
#include <cmath>
#include <queue>
#include <stack>
#include <list>
#include <numeric>
#include <bitset>
#include <ext/algorithm>
#include <ext/numeric>
#define ffor(_a,_f,_t) for(int _a=(_f),__t=(_t);_a<__t;_a++)
#define all(_v) (_v).begin() , (_v).end()
#define sz size()
#define pb push_back
#define SET(__set, val) memset(__set, val, sizeof(__set))
#define FOR(__i, __n) ffor (__i, 0, __n)
typedef long long LL; using namespace std;

int main() {
	int n;
	cin >> n;
	int a[n + 1];
	FOR (i, n)
		cin >> a[i + 1];
	int cnt = 0;
	ffor (i, 1, n + 1)
		if (a[i] < i)
			cnt += a[a[i]] == i;
	cout << cnt << endl;
	return 0;
}

Submission Info

Judge Result