Tanssiaiset

#include <iostream>
using namespace std;
int t[101010];
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  int p1[n/2+1], p2[n/2+1];
  for (int i = 0; i < n/2+1; ++i) {
    cin >> p1[i] >> p2[i];
    t[p1[i]]++;
    t[p2[i]]++;
  }
  for (int i = 0; i < n/2+1; ++i) {
    if (t[p1[i]] == 2 && t[p2[i]] == 2) {
      cout << p1[i] << " " << p2[i] << 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