#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;
typedef vector <int> vec;
#define q are_connected
#define pb push_back
vec a, b; int p[256];
void app() {
for (int i : b) a. pb(i);
b. clear();
}
vec longest_trip(int n, int d) {
srand(114);
for (int i=0; i<n; i++) p[i] = i;
random_shuffle (p, p+n);
a = vec {p[0]}, b = vec {p[1]};
bool f = 0;
for (int _=2; _<n; _++) {
int i = p[_];
if (q({a. back()}, {i})) a. pb(i), f = 0;
else if (f || q({b. back()}, {i})) b. pb(i), f = 1;
else reverse (b. begin(), b. end()), app(), b. pb(i);
}
if (b. empty()) return a;
if (! q(a, b)) return a. size() > b. size() ? a : b;
if (! f && q({a. back()}, {b. back()})) return reverse (b. begin(), b. end()), app(), a;
if (q({a. back()}, b)) {
int l = 0, r = b. size() - 2;
while (l < r) {
int mid = l + r >> 1;
if (q({a. back()}, vec (b. begin(), b. begin() + mid + 1))) r = mid;
else l = mid + 1;
} return rotate (b. begin(), b. begin() + r, b. end()), app(), a;
} else {
int l = 0, r = a. size() - 2;
while (l < r) {
int mid = l + r >> 1;
if (q(vec (a. begin(), a. begin() + mid + 1), b)) r = mid;
else l = mid + 1;
} r ? rotate (a. begin(), a. begin() + r + 1, a. end()), void () : reverse (a. begin(), a. end());
l = 0, r = b. size() - 1;
while (l < r) {
int mid = l + r >> 1;
if (q({a. back()}, vec (b. begin(), b. begin() + mid + 1))) r = mid;
else l = mid + 1;
} return rotate (b. begin(), b. begin() + r, b. end()), app(), a;
}
}
