#include "railroad.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e18;
set<pair<int, int>> byS;
int calc(int s, int t){
byS.erase(make_pair(s, t));
if(byS.empty()) return 0;
auto it = byS.lower_bound(make_pair(t, 0));
if(it == byS.end()){
byS.emplace(s, t);
return -1;
}
int code = calc(it->first, it->second);
if(code == -2) return -2;
if(code == -1){
it = ++byS.lower_bound(make_pair(t, 0));
if(it == byS.end() || calc(it->first, it->second) < 0) return -2;
}
return 0;
}
ll plan_roller_coaster(vector<int> s, vector<int> t) {
int n = (int)s.size();
if(n <= 16){
vector<vector<ll>> dp(1<<n, vector<ll>(n));
for(int msk=1; msk < (1<<n); msk++){
if(__builtin_popcount(msk) == 1) continue;
for(int i = 0; i < n; i++){
if(!(msk & (1<<i))) continue;
dp[msk][i] = INF;
int m = msk^(1<<i);
for(int j = 0; j < n; j++){
if(!(m & (1<<j))) continue;
dp[msk][i] = min(dp[msk][i], dp[m][j] + max(0, t[j]-s[i]));
}
}
}
ll ans = INF;
for(int i = 0; i < n; i++) ans = min(ans, dp[(1<<n)-1][i]);
return ans;
}
else{
for(int i = 0; i < n; i++) byS.emplace(s[i], t[i]);
int code = calc(s[0], t[0]);
if(code == -1) code = calc(s[1], t[1]);
if(code == -2) return 1;
else return 0;
}
}
