Submission #890812

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Source Code Expand

#include <bits/stdc++.h>
#define F first
#define S second
#define X real()
#define Y imag()
using namespace std;
typedef long long ll;
typedef long double ld;

int a[101010];

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n;
	cin>>n;
	for (int i=1;i<=n;i++){
		cin>>a[i];
	}
	int v=0;
	for (int i=1;i<=n;i++){
		if (a[a[i]]==i) v++;
	}
	cout<<v/2<<endl;
}

Submission Info

Judge Result