#include "bits/stdc++.h"
using namespace std;
#define fi first
#define se second
#define mp make_pair
#define pii pair<int,int>
#define pll pair<long long,long long>
#define yes cout<<"Yes\n"
#define no cout<<"No\n"
#define pb push_back
#define sz(x) (int)(x).size()
#define rsz resize
#define ass assign
#define F(i,l,r) for(int i=(l);i<(r);++i)
typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
template<typename T> using pqg = priority_queue<T, vector<T>, greater<T>>;
#define each(a,x) for(auto a:x)
#define FOR(i,a) for(int i=0;i<(a);i++)
#define ROF(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define eb emplace_back
#define ft front()
#define V vector
#include "longesttrip.h"
V<int> longest_trip(int n,int d){
V<int> p1,p2;
p1.pb(0);
F(i,1,n){
if(p2.empty()){
if(are_connected({p1.back()},{i}))p1.pb(i);
else p2.pb(i);
}else{
if(are_connected({p1.back()},{i}))p1.pb(i);
else if(are_connected({p2.back()},{i}))p2.pb(i);
else{
p1.insert(p1.end(),p2.rbegin(),p2.rend());
p2.clear();
p2.pb(i);
}
}
}
if(p2.empty())return p1;
if(are_connected({p1.back()},{p2.ft})){
p1.insert(p1.end(),p2.begin(),p2.end());
return p1;
}
if(are_connected({p1.back()},{p2.back()})){
p1.insert(p1.end(),p2.rbegin(),p2.rend());
return p1;
}
if(are_connected({p1.ft},{p2.ft})){
V<int> merged;
merged.insert(merged.end(),p1.rbegin(),p1.rend());
merged.insert(merged.end(),p2.begin(),p2.end());
return merged;
}
if(are_connected({p1.ft},{p2.back()})){
p2.insert(p2.end(),p1.begin(),p1.end());
return p2;
}
if(sz(p1)>=sz(p2))return p1;
return p2;
}
