Tanssiaiset

#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>
#include <unordered_set>

using namespace std;

int main() {
	
	int n;
	cin >> n;

	unordered_multiset<int> ss;

	for (int i = 0; i < (n/2) + 1; i++) {
		int a;
		int b;
		cin >> a;
		cin >> b;
		
		ss.insert(a);
		ss.insert(b);
	}


	int a = -1;
	int b = -1;

	for (int i = 1; i <= n; i++) {
		if (ss.count(i) >= 2) {
			if (a == -1) a = i;
			else if (b == -1) b = i;
		}
	}

	cout << a << " " << b << endl;
	return 0;
}

Test 1

Group: 1

Verdict: WRONG ANSWER

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: WRONG ANSWER

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: WRONG ANSWER

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: WRONG ANSWER

Test 9

Group: 2

Verdict: WRONG ANSWER

Test 10

Group: 2

Verdict: WRONG ANSWER