#include "stations.h"
#include <bits/stdc++.h>
using namespace std;
vector<int> label(int n, int k, vector<int> u, vector<int> v) {
vector<int> deg(n);
vector<vector<int>> adj(n);
for (int i = 0; i < n - 1; i++)
deg[u[i]]++, deg[v[i]]++, adj[u[i]].push_back(v[i]), adj[v[i]].push_back(u[i]);;
vector<int> labels(n);
function<void(int,int)> init = [&](int u, int p) {
if (~p) adj[u].erase(find(adj[u].begin(), adj[u].end(), p));
for (int v: adj[u])
init(v, u);
};
init(0, -1);
// function<void(int,int)> dfs;
// function<void(int,int,int,int)> join = [&](int u, int l, int r, int v) {
// if (l > r) return;
// if (l == r)
// dfs(adj[u][l], 2*v+1);
// else {
// int m = (l+r) / 2;
// join(u, l, m, v*2+1);
// join(u, m+1, r, v*2+2);
// }
// };
// dfs = [&](int u, int l) {
// labels[u] = l;
// join(u, 0, adj[u].size()-1, l);
// };
int l = 0;
function<void(int,int)> dfs = [&](int u, int d) {
if (d == 0)
labels[u] = l++;
for (int v: adj[u])
dfs(v, d ^ 1);
if (d == 1)
labels[u] = l++;
};
dfs(0, 0);
return labels;
}
int find_next_station(int s, int t, vector<int> c) {
sort(c.begin(), c.end());
for (int i: c)
if (i == t)
return i;
if (c.size() > 1) {
if (s < c[0]) { // d = 0
int l = s;
for (int i = 0; i+1 < c.size(); i++) {
if (l <= t && t <= c[i])
return c[i];
l = c[i];
}
return c.back();
} else { // d = 1
c.push_back(s);
int l = c[1];
for (int i = 2; i < c.size(); i++) {
if (l <= t && t <= c[i])
return l;
l = c[i];
}
}
}
return c[0];
}
