#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;
int N;
const int MAXN = 256;
vector<int> adj[MAXN];
void connect(vector<int>& path1, vector<int>& path2) {
reverse(begin(path2), end(path2));
for (int j = 0; j < (int)path2.size(); ++j) {
path1.push_back(path2[j]);
}
path2.clear();
}
std::vector<int> longest_trip(int _N, int D)
{
N = _N;
vector<int> idx(N);
iota(begin(idx), end(idx), 0);
mt19937 rng(0);
shuffle(begin(idx), end(idx), rng);
bool not_connected = false;
vector<int> path1{idx[0]}, path2{idx[1]};
for (int j = 2; j < N; ++j) {
int i = idx[j];
if (are_connected({path1.back()}, {i})) {
path1.push_back(i);
not_connected = false;
} else {
if (not_connected) {
path2.push_back(i);
} else {
if (are_connected({path2.back()}, {i})) {
not_connected = true;
path2.push_back(i);
} else {
connect(path1, path2);
path2 = {i};
not_connected = false;
}
}
}
}
if (path1.size() < path2.size()) swap(path1, path2);
if (path2.size() == 0) return path1;
if (!are_connected(path1, path2)) return path1;
// if (are_connected({path1.back()}, {path2.back()})) {
// connect(path1, path2);
// return path1;
// }
// reverse(begin(path1), end(path1));
// if (are_connected({path1.back()}, {path2.back()})) {
// connect(path1, path2);
// return path1;
// }
// reverse(begin(path1), end(path1));
// reverse(begin(path2), end(path2));
// if (are_connected({path1.back()}, {path2.back()})) {
// connect(path1, path2);
// return path1;
// }
// reverse(begin(path1), end(path1));
// if (are_connected({path1.back()}, {path2.back()})) {
// connect(path1, path2);
// return path1;
// }
// reverse(begin(path1), end(path1));
// reverse(begin(path2), end(path2));
// cerr << "Path1 = ";
// for (auto& u : path1) {
// cerr << u << " ";
// }
// cerr << "\nPath2 = ";
// for (auto& u : path2) {
// cerr << u << " ";
// }
// cerr << "\n";
vector<int> super_path;
int l1 = 0, r1 = (int)path1.size();
int l2 = 0, r2 = (int)path2.size();
while (r1 - l1 > 1) {
int m1 = (l1 + r1) / 2;
if (are_connected(vector<int>(begin(path1) + l1, begin(path1) + m1),
vector<int>(begin(path2) + l2, begin(path2) + r2))) {
r1 = m1;
} else {
l1 = m1;
}
}
while (r2 - l2 > 1) {
int m2 = (l2 + r2) / 2;
if (are_connected(vector<int>(begin(path1) + l1, begin(path1) + r1),
vector<int>(begin(path2) + l2, begin(path2) + m2))) {
r2 = m2;
} else {
l2 = m2;
}
}
assert(l1 < (int)path1.size());
assert(l2 < (int)path2.size());
vector<int> res;
for (int i = l1; i < (int)path1.size(); ++i) {
res.push_back(path1[i]);
}
for (int i = 0; i < l1; ++i) {
res.push_back(path1[i]);
}
reverse(begin(res), end(res));
for (int i = l2; i < (int)path2.size(); ++i) {
res.push_back(path2[i]);
}
for (int i = 0; i < l2; ++i) {
res.push_back(path2[i]);
}
return res;
}
