#include "longesttrip.h"
#include <bits/stdc++.h>
#include <vector>
#define MP make_pair
#define f first
#define s second
typedef long long ll;
using namespace std;
mt19937_64 rnd(286);
const int INF = (int)1e6;
bool conectados(int A, int B) {
vector<int> a,b;
a.push_back(A);
b.push_back(B);
return are_connected(a,b);
}
struct linea{
deque <int> lin;
linea(){}
linea(int A) {
lin.push_front(A);
}
void unir(linea B) {
while (!B.lin.empty()) {
lin.push_front(B.lin.front());
B.lin.pop_front();
}
return;
}
};
vector <int> base(int N) {
vector <int> ans;
ans.push_back(0);
if (conectados(0, 1)) ans.push_back(1);
return ans;
}
std::vector<int> longest_trip(int N, int D) {
if (N <= 2) return base(N);
vector <linea> V;
vector <int> ans;
for (int i = 0; i < N; i++)
V.push_back(linea(i));
shuffle(V.begin(),V.end(),rnd);
while (V.size() >= 3) {
linea A = V.back();
V.pop_back();
linea B = V.back();
V.pop_back();
linea C = V.back();
V.pop_back();
if (conectados(A.lin.front(), B.lin.front())) {
A.unir(B);
V.push_back(A);
V.push_back(C);
}
else if (conectados(A.lin.front(), C.lin.front())) {
A.unir(C);
V.push_back(A);
V.push_back(B);
}
else {
B.unir(C);
V.push_back(B);
V.push_back(A);
}
}
if (V[0].lin.size() > V[1].lin.size()) swap(V[0], V[1]);
while (!V[1].lin.empty()) {
ans.push_back(V[1].lin.front());
V[1].lin.pop_front();
}
return ans;
}
