Submission #890785

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> PII;
typedef long long ll;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pct __builtin_popcount

#define N 100100
int n, a[N];

int main () {
	cin >> n;
	for (int i = 1; i <= n; i ++) cin >> a[i];
	int S = 0;
	for (int i = 1; i <= n; i ++)
		if (a[a[i]] == i) S ++;
	cout << S/2 << endl;
	return 0;
}

Submission Info

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