Submission #7106178

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define INF 1LL<<62
#define inf 1000000007

ll a[100010];
int main() {
	ll n;
	cin>>n;
	for(int i=0;i<n;i++){
		ll x;
		cin>>x;
		x--;
		a[i]=x;
	}
	ll ans=0;
	for(int i=0;i<n;i++){
		ll now=a[i];
		if(a[now]==i){
			ans++;
		}
	}
	cout << ans/2;
	return 0;
}

Submission Info

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