#include "longesttrip.h"
#include<bits/stdc++.h>
#include<random>
using namespace std;
const int MAXN=260;
mt19937 mt(666);
int n;
vector<int> v;
vector<int> path[2];
int edge[MAXN][MAXN];
bool ask(int x,int y)
{
if(edge[x][y]==1) return 1;
if(edge[x][y]==0) return 0;
if(are_connected({x}, {y})) ///
{
edge[x][y]=edge[y][x]=1;
return 1;
}
edge[x][y]=edge[y][x]=0;
return 0;
}
bool checkEnds()
{
vector<int> t0={path[0][0], path[0].back()};
vector<int> t1={path[1][0], path[1].back()};
if(t0[0]==t0[1]) t0.pop_back();
if(t1[0]==t1[1]) t1.pop_back();
if(!are_connected(t0,t1)) return 0;
// if(t0.size()==1 && t1.size()==1) return 1;
if(t0.size()==1)
{
if(!ask(t0[0], t1[0])) reverse(path[1].begin(), path[1].end());
path[0].insert(path[0].end(), path[1].begin(), path[1].end());
return 1;
}
if(t1.size()==1)
{
if(!ask(t0.back(), t1[0])) reverse(path[0].begin(), path[0].end());
path[0].push_back(t1[0]);
return 1;
}
if(are_connected({t0.back()}, t1))
{
if(!ask(t0.back(), t1[0])) reverse(path[1].begin(), path[1].end());
path[0].insert(path[0].end(), path[1].begin(), path[1].end());
return 1;
}
else
{
reverse(path[0].begin(), path[0].end());
if(!ask(t0[0], t1[0])) reverse(path[1].begin(), path[1].end());
path[0].insert(path[0].end(), path[1].begin(), path[1].end());
return 1;
}
}
std::vector<int> longest_trip(int N, int D)
{
n=N;
path[0].clear(); path[1].clear();
v.clear();
for(int i=0;i<n;i++) v.push_back(i);
shuffle(v.begin(), v.end(), mt);
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++) edge[i][j]=edge[j][i]=-1;
}
path[0].push_back(v[0]);
bool fl=0;
for(int i=1;i<n;i++)
{
if(ask(path[0].back(), v[i]))
{
path[0].push_back(v[i]);
fl=0;
continue;
}
if(path[1].empty())
{
path[1].push_back(v[i]);
fl=1;
continue;
}
if(fl)
{
path[1].push_back(v[i]);
fl=1;
continue;
}
if(ask(path[1].back(), v[i]))
{
path[1].push_back(v[i]);
fl=1;
continue;
}
path[0].insert(path[0].end(), path[1].rbegin(), path[1].rend());
if(path[1].size()==1) fl=1;
else fl=0;
path[1].clear();
path[1].push_back(v[i]);
}
if(path[1].empty()) return path[0];
if(!are_connected(path[0], path[1]))
{
if(path[0].size()>=path[1].size()) return path[0];
else return path[1];
}
else
{
if(checkEnds()) return path[0];
int l=0, r=path[0].size();
while(l<r)
{
int mid=(l+r)/2;
vector<int> tmp(path[0].begin()+l, path[0].begin()+mid+1);
if(are_connected(tmp, path[1])) r=mid;
else l=mid+1;
}
int ind0=l;
l=0, r=path[1].size();
while(l<r)
{
int mid=(l+r)/2;
vector<int> tmp(path[1].begin()+l, path[1].begin()+mid+1);
if(are_connected({path[0][ind0]}, tmp)) r=mid;
else l=mid+1;
}
int ind1=l;
vector<int> ret;
for(int i=ind0-1;i>=0;i--) ret.push_back(path[0][i]);
for(int i=path[0].size()-1;i>=ind0;i--) ret.push_back(path[0][i]);
for(int i=ind1;i>=0;i--) ret.push_back(path[1][i]);
for(int i=path[1].size()-1;i>ind1;i--) ret.push_back(path[1][i]);
return ret;
}
}
