#include "longesttrip.h"
#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
//#define int long long
#define pii pair<int,int>
#define vi vector<int>
#define ff first
#define ss second
#define sp << " " <<
#define all(x) x.begin(),x.end()
#define big(x) ((int)(x.size()))
using namespace std;
const int MOD = 1e9+7, LIM = 1e6+1, inf = 2e9;
std::vector<int> longest_trip(int N, int D)
{
deque<int> trip;
if (D == 3) {
for (int i=0;i<N;i++) trip.push_back(i);
return vi(all(trip));
}
if (D == 2) {
vi have(N,0);
if (are_connected({0},{1})) {
trip.push_back(0);
trip.push_back(1);
have[0] = have[1] = 1;
}
else {
trip.push_back(0);
trip.push_back(2);
have[0] = have[2] = 1;
}
for (int i=1;i<N;i++) {
if (have[i]) continue;
if (are_connected({i},{trip.back()})) trip.push_back(i);
else trip.push_front(i);
}
vi ans;
while (!trip.empty()) {
ans.push_back(trip.front());
trip.pop_front();
}
return ans;
}
return {};
}
