Submission #891318

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Source Code Expand

#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <numeric>
#include <string>

using namespace std;

int main(void){
	int n; cin >> n;
	vector <vector <int> > v(n, vector <int>(n));
	for(int i=0; i<n; i++){
		int t; cin >> t;
		v[i][t]=1;
	}
	int res=0;
	for(int i=0; i<n; i++){
		for(int j=0; j<n; j++){
			if(v[i][j]==1 && v[j][i]==1){
				res++;
			}
		}
	}
	cout << res << endl;
	return 0;
}

Submission Info

Judge Result