#include "stations.h"
#include <bits/stdc++.h>
using namespace std;
constexpr int N = (int)2e3 + 1;
int tin[N],tout[N];
int timer = 0;
vector<int> g[N];
mt19937 rnd(time(nullptr));
void dfs(int v,int pr = -1){
tin[v] = timer++;
for(auto& to : g[v]){
if(to == pr) continue;
dfs(to,v);
}
tout[v] = timer++;
return;
}
std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
for(int i = 0; i < n-1; i++){
g[u[i]].push_back(v[i]);
g[v[i]].push_back(u[i]);
}
dfs(0);
vector<int> labels(n);
for(int i = 0; i < n; i++){
labels[i] = tin[i] * N + tout[i];
}
return labels;
}
bool upper(int tinA,int toutA,int tinB,int toutB){
return tinA <= tinB && toutA >= toutB;
}
int find_next_station(int s, int t, std::vector<int> c) {
int tinS = s / N, toutS = s % N;
int tinT = t / N, toutT = t % N;
int pr = 0;
for(auto& to : c){
int tin = to / N, tout = to % N;
if(upper(tin,tout,tinS,toutS)){
pr = to;
continue;
}
if(upper(tin,tout,tinT,toutT))
return to;
}
return pr;
}
