#include "railroad.h"
#include<bits/stdc++.h>
#define x first
#define y second
#define pb push_back
#define eb emplace_back
#define all(a) (a).begin(),(a).end()
#define SZ(a) (int)(a).size()
#define FOR(i, a, b) for(int i=(a); i<=(b); ++i)
#define ROF(i, a, b) for(int i=(a); i>=(b); --i)
#define make_unique(a) sort(all((a))), (a).resize(unique(all((a)))-(a).begin())
using namespace std;
typedef pair<int,int> PII;
typedef long long LL;
typedef double DD;
typedef long double LD;
typedef pair<LL,LL> PLL;
typedef pair<DD,DD> PDD;
typedef vector<int> VI;
typedef vector<LL> VL;
const int N = 400004;
int n;
vector<int> mark, comp, dp, g[N];
queue<int> bfs;
LL plan_roller_coaster(VI s, VI t) {
int n = SZ(s);
FOR(i,0,n-1) comp.pb(s[i]), comp.pb(t[i]);
comp.pb(0); comp.pb(1e9+2);
make_unique(comp);
int m = SZ(comp);
dp.resize(m, 0);
mark.resize(m, 0);
FOR(i,0,n-1){
s[i] = lower_bound(all(comp), s[i])-comp.begin();
t[i] = lower_bound(all(comp), t[i])-comp.begin();
if(s[i] == t[i]) continue;
dp[s[i]]++;
dp[t[i]]--;
g[s[i]].pb(t[i]);
}
--dp[1];
g[0].pb(1);
FOR(i, 1, m-2){
if(dp[i] > 0) return 1;
while(dp[i] < 0) g[i].pb(i+1), ++dp[i], --dp[i+1];
}
// check if the same component
bfs.push(0);
int cnt = 0;
while(!bfs.empty()){
int u = bfs.front();
++cnt;
bfs.pop();
for(int e : g[u]){
if(mark[e]) continue;
mark[e] = 1;
bfs.push(e);
}
}
if(cnt == m) return 0;
return 1;
}
