#ifndef rtgsp
#include "stations.h"
#endif
#include<bits/stdc++.h>
#define ll long long
#define task ""
using namespace std;
const int maxn = 1e5 + 1;
int t, d[maxn], tin[maxn], tout[maxn];
vector<int> adj[maxn], L, L2;
void dfs (int u, int p)
{
tin[u] = t++;
for (int v : adj[u])
{
if (v == p) continue;
d[v] = d[u] + 1;
dfs(v, u);
}
tout[u] = t++;
if (d[u] & 1) L[u] = L2[u] = tout[u];
else L[u] = L2[u] = tin[u];
}
vector<int> label (int n, int k, vector<int> u, vector<int> v)
{
t = 0;
for (int i = 0; i < n; i++)
{
adj[i].clear();
tin[i] = tout[i] = 0;
}
L.resize(n, 0);
L2.resize(n, 0);
for (int i = 0; i < n - 1; i++)
{
adj[u[i]].push_back(v[i]);
adj[v[i]].push_back(u[i]);
}
dfs(0, -1);
sort(L2.begin(), L2.end());
for (int i = 0; i < n; i++)
L[i] = lower_bound(L2.begin(), L2.end(), L[i]) - L2.begin();
return L;
}
int find_next_station (int s, int t, vector<int> c)
{
bool ok = 0;
if (s > c.back()) ok = 1;
if (ok)
{
if (t <= c[0] || t > s) return c[0];
c.push_back(s);
for (int i = 1; i < (int)c.size() - 1; i++)
if (t >= c[i] && t < c[i + 1])
return c[i];
}
else
{
if (t < s || t >= c.back()) return c.back();
c.insert(c.begin(), s);
for (int i = 1; i < (int)c.size(); i++)
if (t > c[i - 1] && t <= c[i])
return c[i];
}
return -1;
}
#ifdef rtgsp
int main()
{
//freopen(task".INP", "r", stdin);
//freopen(task".OUT", "w", stdout);
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
vector<int> L = label(5, 10, {0, 1, 1, 2}, {1, 2, 3, 4});
for (int i : L) cout << i << " ";
cout << '\n';
cout << find_next_station(1, 0, {2, 4}) << '\n';
cout << find_next_station(4, 3, {0, 1, 3}) << '\n';
}
#endif
