#include "stations.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector <ll>;
using vi = vector <int>;
static void dfs (ll u, ll par, ll dep, vi &ans, vector <vll> &adj, ll &timer) {
if (!(dep&1)) ans[u] = timer++;
for (ll v : adj[u]) {
if (v == par) continue;
dfs(v, u, dep+1, ans, adj, timer);
}
if (dep&1) ans[u] += timer++;
}
vi label (int n, int k, vi vu, vi vv) {
vector <vll> adj(n, vll({}));
for (ll i = 0; i < n-1; i++) {
adj[vu[i]].push_back(vv[i]);
adj[vv[i]].push_back(vu[i]);
}
vi ans(n);
ll timer = 0;
dfs(0, 0, 0, ans, adj, timer);
return ans;
}
int find_next_station (int s, int t, vi c) {
bool isTin = s < c[0];
if (isTin) { // subtree of s has >= s
bool isUp = (t < s || (c.size() == 1 ? true : t > c[c.size()-2])) && s != 0; // s==0: s is root
if (isUp) {
return c[c.size()-1]; // highest tout -> my par
} else {
return *lower_bound(c.begin(), c.end(), t); // first tout above t
}
} else { // subtree of s has <= s
bool isUp = t > s || (c.size() == 1 ? true : t < c[1]);
if (isUp) {
return c[0]; // lowest tin -> my par
} else {
return *(--upper_bound(c.begin(), c.end(), t)); // tout above t, minus 1 pos
}
}
}
