Submission

Score: 100

User: vachirasawin

Problemset: วันว่างๆ

Language: cpp

Time: 0.016 second

Submitted On: 2026-03-13 17:17:20

// grader-chan
// c2_st66_freeday.cpp | c2_st66_freeday

#include <bits/stdc++.h>
using namespace std;

int N, M;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    cin >> N;

    vector<pair<int, int>> v;
    for (int i = 0; i < N; i++) {
        cin >> M;

        for (int j = 0; j < M; j++) {
            int s, e;
            cin >> s >> e;
            v.push_back({s, e});
        }
    }
    sort(v.begin(), v.end());

    vector<pair<int, int>> merged;
    for (auto [l, r] : v) {
        if (merged.empty() || merged.back().second < l) {
            merged.push_back({l,r});
        } else {
            merged.back().second = max(merged.back().second, r);
        }
    }

    if (merged.size() == 1) {
        cout << -1;
    } else {
        cout << merged[0].second << " ";

        for(int i = 1; i < merged.size() - 1; i++){
          cout << merged[i].first << " " << merged[i].second << " ";
        }
        cout << merged[merged.size() - 1].first << " ";
    }


    return 0;
}