Tanssiaiset

// TERVEISIÄ KAIKILLE OLARILAISILLE!!
#include <iostream>
#include <unordered_set>
#include <vector>
using namespace std;

int main() {
    long long d, n, e, t;
    vector<long long> v;
    unordered_multiset<long long> s, m;
    unordered_multiset<string> b;
    cin >> d;
    n = d / 2 + 1;
    for (long long i = 0; i < n; i++) {
        cin >> e >> t;
        s.insert(e);
        m.insert(t);
        b.insert(to_string(e) + ' ' + to_string(t));
    }
    for (long long i = 1; i <= d; i++) {
        if (s.count(i) + m.count(i) > 1) {
            v.push_back(i);
        }
    }
    if (b.count(to_string(v[0]) + ' ' + to_string(v[1])) > 0) {
        cout << v[0] << ' ' << v[1] << endl;
    } else {
        cout << v[1] << ' ' << v[0] << endl;
    }
}

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