#include "railroad.h"
#include <bits/stdc++.h>
using namespace std;
#define rall(s) s.rbegin(), s.rend()
#define all(s) s.begin(), s.end()
#define sz(s) (int)s.size()
#define s second
#define f first
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int N = 1e6, inf = 1e9 + 5;
int pr[N], sz[N];
int get(int x) {
if (pr[x] == x) return x;
return pr[x] = get(pr[x]);
}
void unite(int a, int b) {
a = get(a);
b = get(b);
if (a == b) return;
if (sz[a] > sz[b]) swap(a, b);
pr[a] = b, sz[b] += sz[a];
}
ll plan_roller_coaster(vector<int> s, vector<int> t) {
vector<int> x;
t.push_back(1);
s.push_back(inf);
for (int v: s) x.push_back(v);
for (int v: t) x.push_back(v);
sort(all(x));
x.erase(unique(all(x)), x.end());
int n = sz(s), m = sz(x);
vector<int> cnt(m);
for (int i = 0; i < m; i++) pr[i] = i, sz[i] = 1;
for (int i = 0; i < n; i++) {
s[i] = lower_bound(all(x), s[i]) - x.begin();
t[i] = lower_bound(all(x), t[i]) - x.begin();
unite(s[i], t[i]);
if (s[i] <= t[i]) cnt[s[i]]++, cnt[t[i]]--;
else cnt[s[i]]--, cnt[t[i]]++;
}
for (int i = 0; i < m; i++) {
if (i) cnt[i] += cnt[i - 1];
if (cnt[i] < 0) unite(i, i + 1);
else if (cnt[i] > 0) return 1;
}
for (int i = 1; i < m; i++) {
if (get(i) != get(i - 1)) return 1;
}
return 0;
}
