Tanssiaiset

input/code.cpp: In function 'int main()':
input/code.cpp:28:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < parit.size(); i++) {
                    ^

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

using namespace std;

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

	vector<pair<int,int>> parit;
	unordered_multiset<int> bb;

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

		bb.insert(a);
		bb.insert(b);

		parit.push_back(make_pair(a,b));
	}

	for (int i = 0; i < parit.size(); i++) {
		int a = parit[i].first;
		int b = parit[i].second;

		if (bb.count(a) >= 2 && bb.count(b) >= 2) {
			cout << a << " " << b << endl;
		}
	}
	
	return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED