Submission #890915

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Source Code Expand

#include <string>
#include <queue>
#include <stack>
#include <vector>
#include <sstream>
#include <algorithm>
#include <deque>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <list>
#include <cstdio>
#include <iostream>
#include <cmath>
#include <climits>
#include <bitset>
#include <functional>
#include <numeric>
#include <ctime>
#include <cassert>
#include <cstring>
#include <fstream>

using namespace std;


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

	return 0;
}

Submission Info

Judge Result