C_Электрички_N^2

#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
#include <functional>
#include <map>
#include <set>

using namespace std;

//метод update для построения графа: компонента связности = станция
//трелки идут от более ранних электричек к более поздним

//color: 0 - белый, 1 - серый, 2 - черный
void dfs(int v, vector <vector <int> >& gr, vector <int>& TopSort, vector <int>& color) {
    if (color[v] == 2 || color[v] == 1) return;
    color[v] = 1;
    for (int u : gr[v]) {
        dfs(u, gr, TopSort, color);
    }
    color[v] = 2;
    TopSort.push_back(v);
}


int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int N;
    cin >> N;
    vector < pair <pair <int, int> , pair <int, int> > > TRAIN(N+1); //A {station, time}, B {station, time}
    for (int i = 1; i < N + 1; ++i) {
        int from, to, from_time, pace, to_time;
        cin >> from >> to >> from_time >> pace;
        to_time = (to - from) * pace + from_time;
        pair <int, int> A = { from, from_time };
        pair <int, int> B = { to, to_time };
        TRAIN[i] = { A,B };
    }
    /*cout << '\n';
    for (auto x : TRAIN) {
        auto A = x.first;
        auto B = x.second;
        cout << A.first << ' ' << A.second << '\n';
        cout << B.first << ' ' << B.second << '\n' << '\n';
    }cout << '\n';*/
    vector <vector <pair <int, int> > > STAT; //stations
    set <int> used_stat;
    for (int i = 1; i < N+1; ++i) {
        auto A = TRAIN[i].first;
        int from = A.first;
        if (used_stat.find(from) == used_stat.end()) {
            vector <pair <int, int> > stat_from;
            int from_time = A.second;
            stat_from.push_back({from_time, i });
            for (int j = 1; j < N + 1 && j != i; ++j) {
                auto A_some = TRAIN[j].first;
                int from_some = A.first;
                int from_time_some = A.second;
                if (from_some == from && used_stat.find(from_some) == used_stat.end()) {
                    stat_from.push_back({ from_time_some, from_some });
                }
                auto B_some = TRAIN[j].second;
                int to_some = B_some.first;
                int to_time_some = B_some.second;
                if (to_some == from && used_stat.find(to_some) == used_stat.end()) {
                    stat_from.push_back({ to_time_some, to_some });
                }
            }
            sort(stat_from.begin(), stat_from.end());
            STAT.push_back(stat_from);
            used_stat.insert(from);
        }
        auto B = TRAIN[i].second;
        int to = B.first;
        if (used_stat.find(to) == used_stat.end()) {
            vector <pair <int, int> > stat_to;
            int to_time = B.second;
            stat_to.push_back({ to_time, i });
            for (int j = 1; j < N + 1 && j != i; ++j) {
                auto A_some = TRAIN[j].first;
                int from_some = A_some.first;
                int from_time_some = A.second;
                if (from_some == to && used_stat.find(from_some) == used_stat.end()) {
                    stat_to.push_back({ from_time_some, from_some });
                }
                auto B_some = TRAIN[j].second;
                int to_some = B.first;
                int to_time_some = B.second;
                if (to_some == to && used_stat.find(to_some) == used_stat.end()) {
                    stat_to.push_back({ to_time_some, to_some });
                }
            }
            sort(stat_to.begin(), stat_to.end());
            STAT.push_back(stat_to);
            used_stat.insert(to);
        }
    }
    cout << "ONE\n";
    vector <vector <int> > gr(N+1);
    for (int i = 0; i < STAT.size(); ++i) {
        for (int j = 0; j < (int)STAT[i].size() - 1; ++j) {
            int faster = STAT[i][j].second;
            int  slower = STAT[i][j + 1].second;
            cout << "slower = " << slower << '\n';
            gr[faster].push_back(slower);
        }
    }
    for (int i = 1; i < N + 1; ++i) {
        for (auto j : gr[i]) {
            cout << j << ' ';
        }cout << '\n';
    }cout << '\n';
}