#include "railroad.h"
#include <map>
#include <set>
#include <utility>
#define MAXN 200005
using namespace std;
multiset<pair<int,int> > R, R2, R3; // [t,s], [s,t], [t,s]
long long plan_roller_coaster(std::vector<int> s, std::vector<int> t) {
int N = (int) s.size();
for (int i=0; i<N; i++) {
R.insert({t[i], s[i]});
R2.insert({s[i], t[i]});
}
R.insert({1, 1<<30});
R2.insert({1<<30, 1});
while (R.size() > 1) {
pair<int,int> cur = *R.rbegin();
R.erase(--R.end());
if (R2.find({cur.second, cur.first}) != R2.end()) {
R2.erase(R2.find({cur.second, cur.first}));
} else {
R3.erase(R3.find(cur));
}
while (R2.size() && (*R2.rbegin()).first >= cur.first) {
R3.insert({(*R2.rbegin()).second,(*R2.rbegin()).first});
R2.erase(--R2.end());
}
if (R3.size()) {
R.erase(*R3.rbegin());
R.insert({(*R3.rbegin()).first, cur.second});
R2.insert({cur.second, (*R3.rbegin()).first});
R3.erase(--R3.end());
} else {
return(42069);
}
}
return(0);
}
