#ifndef hwe
#include "stations.h"
#endif
#include <bits/stdc++.h>
using namespace std;
#define POPCOUNT(n) (__builtin_popcountll((n)))
#define CLZ(n) (__builtin_clzll((n)))
#define CTZ(n) (__builtin_ctzll((n)))
#define LOG(n) (63 - __builtin_clzll((n)))
#define BIT(n, i) (((n) >> (i)) & 1ll)
#define MASK(i) (1ll << (i))
#define FLIP(n, i) ((n) ^ (1ll << (i)))
#define ON(n, i) ((n) | MASK(i))
#define OFF(n, i) ((n) & ~MASK(i))
#define Int __int128
#define fi first
#define se second
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long long, int> pli;
typedef pair<int, long long> pil;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vll;
typedef vector<pair<long long, int>> vli;
typedef vector<pair<int, long long>> vil;
template <class T1, class T2> bool maximize(T1 &x, T2 y) {
if (x < y) {
x = y;
return true;
}
return false;
}
template <class T1, class T2> bool minimize(T1 &x, T2 y) {
if (x > y) {
x = y;
return true;
}
return false;
}
template <class T> void remove_duplicate(vector<T> &ve) {
sort (ve.begin(), ve.end());
ve.resize(unique(ve.begin(), ve.end()) - ve.begin());
}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
template <class T1, class T2> T1 random(T1 l, T2 r) {
return uniform_int_distribution<T1>(l, r)(rng);
}
template <class T> T random(T r) {
return rng() % r;
}
const int N = 1e6 + 5;
const int MOD = 1e9 + 7;
const int inf = 1e9;
const long long INF = 1e18;
int sz[N];
vector<int> adj[N];
void count_child(int u, int fa) {
sz[u] = 1;
for (auto v : adj[u]) if (v != fa) {
count_child(v, u);
sz[u] += sz[v];
}
}
void dfs(int u, int fa, int depth, int L, int R, vector<int> &labels) {
if (depth & 1) labels[u] = R--;
else labels[u] = L++;
for (auto v : adj[u]) if (v != fa) {
dfs(v, u, depth + 1, L, L + sz[v] - 1, labels);
L += sz[v];
}
}
vector<int> label(int n, int k, vector<int> u, vector<int> v) {
vector<int> labels(n);
for (int i = 0; i < n; ++i) adj[i].clear();
for (int i = 0; i < u.size(); ++i) {
adj[u[i]].emplace_back(v[i]);
adj[v[i]].emplace_back(u[i]);
}
count_child(0, -1);
dfs(0, -1, 0, 0, n - 1, labels);
return labels;
}
int find_next_station(int s, int t, vector<int> c) {
if (c.size() == 1) return c[0];
if (s > c.back()) { // depth of s is odd
int fa = c[0], L = c[1], R = s;
if (t < L || t > R) return fa; // t is not in subtree of s
// return the largest label that <= t
return c[upper_bound(c.begin(), c.end(), t) - c.begin() - 1];
}
else { // depth of s is even
int fa = (s == 0 ? -1 : c.back());
if (fa != -1) c.pop_back();
int L = s, R = c.back();
if (t < L || t > R) return fa;
// return the smallest label that >= t
return c[lower_bound(c.begin(), c.end(), t) - c.begin()];
}
return -1;
}
#ifdef hwe
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cerr << '\n'; return 0;
}
#endif
