#include "stations.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
template<typename T>
int len(T &a){return a.size();}
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
vector<int> label(int n, int k, vector<int> u, vector<int> v) {
vector<vector<int>> g(n);
for(int i = 0; i < n - 1;i ++){
g[u[i]].push_back(v[i]);
g[v[i]].push_back(u[i]);
}
int st = 0;
for(int i = 1; i < n; i ++) if(len(g[i]) == 1) st = i;
vector<int> res(n);
iota(all(res), 0);
return res;
int cur = 0;
auto dfs = [&](auto &dfs, int i, int p = -1)->void{
res[i] = cur ++;
for(auto u : g[i]){
if(u == p) continue;
dfs(dfs, u, i);
}
};
dfs(dfs, st);
return res;
}
int find_next_station(int s, int t, vector<int> c) {
if(len(c) == 1){
return c[0];
}
s ++; t ++;
string a = "", b = "";
do{
a.push_back(s % 2 + '0');
s /= 2;
}while(s);
do{
b.push_back(t % 2 + '0');
t /= 2;
}while(t);
reverse(all(a));
reverse(all(b));
if(len(a) >= len(b) || b.substr(0, len(a)) != a){
return c[0];
}
return c[b[len(a)] - '0' + (a != "1")];
}
