#include "longesttrip.h"
#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;
vector<int> longest_trip(int n, int D){
vector<int> A = {0}, B = {};
for(int i = 1; i < n; i++){
if(B.empty()){
if(are_connected({A.back()}, {i})) A.push_back(i);
else if(are_connected({A[0]}, {i})) A.insert(A.begin(), i);
else B = {i};
}
else{
if(are_connected({A.back()}, {i})) A.push_back(i);
else if(are_connected({B.back()}, {i})) B.push_back(i);
else{
reverse(B.begin(), B.end());
A.insert(A.end(), B.begin(), B.end());
B.clear();
i--;
}
}
if(A.size() < B.size()) swap(A, B);
}
int na = A.size(), nb = B.size();
int ans = nb, x = -1, y = -1;
for(int i = 0; i < nb; i++){
if(!are_connected({B[i]}, A)) continue;
int l = 0, r = na-1;
while(l < r){
int m = (l+r)/2;
vector<int> s;
for(int j = 0; j <= m; j++) s.push_back(A[j]);
if(are_connected({B[i]}, s)) r = m;
else l = m+1;
}
if(max(i+1, nb-i)+max(l+1, na-l) > ans){
ans = max(i+1, nb-i)+max(l+1, na-l), x = l, y = i;
}
l = 0, r = na-1;
while(l < r){
int m = (l+r+1)/2;
vector<int> s;
for(int j = m; j < na; j++) s.push_back(A[j]);
if(are_connected({B[i]}, s)) l = m;
else r = m-1;
}
if(max(i+1, nb-i)+max(l+1, na-l) > ans){
ans = max(i+1, nb-i)+max(l+1, na-l), x = l, y = i;
}
}
vector<int> C = A;
if(x != -1){
C.clear();
if(na > 1 && are_connected({A[0]}, {A.back()})){
for(int i = x+1; i <= na+x; i++) C.push_back(A[i%na]);
}
else if(na-x > x+1){
for(int i = na-1; i >= x; i--) C.push_back(A[i]);
}
else{
for(int i = 0; i <= x; i++) C.push_back(A[i]);
}
if(nb > 1 && are_connected({B[0]}, {B.back()})){
for(int i = y; i < nb+y; i++) C.push_back(B[i%nb]);
}
else if(nb-y > y+1){
for(int i = y; i < nb; i++) C.push_back(B[i]);
}
else{
for(int i = y; i >= 0; i--) C.push_back(B[i]);
}
}
return C;
}
