#include "railroad.h"
#include <bits/stdc++.h>
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
using namespace std;
#define X first
#define Y second
#define pb push_back
typedef pair<int, int> ii;
typedef long long ll;
const int maxn = 18;
ll dp[maxn][1<<maxn];
int n;
const int maxN = 4e5+5;
int sw[maxN];
vector<int> adj[maxN];
int s[maxN], t[maxN];
ll solve(int u, int bit)
{
if(bit == (1<<n)-1) return 0;
if(dp[u][bit] != -1) return dp[u][bit];
ll best = 1e18;
for(int i = 0; i< n; i++)
{
if(bit&(1<<i)) continue;
best = min(best, (t[u]<= s[i]?0:t[u]-s[i])+solve(i, bit|(1<<i)));
}
return dp[u][bit] = best;
}
int col[maxN];
void ff(int u)
{
col[u] = 1;
for(int v : adj[u])
{
if(!col[v]) ff(v);
}
}
ll plan_roller_coaster(vector<int> S, vector<int> T)
{
n = S.size();
for(int i = 0; i< n; i++)
{
s[i] = S[i];
t[i] = T[i];
}
if(n<= 16)
{
memset(dp, -1, sizeof dp);
ll best = 1e18;
for(int i = 0; i< n; i++) best = min(best, solve(i, 1<<i));
return best;
}
vector<int> all;
for(int i = 0; i< n; i++)
{
all.pb(s[i]); all.pb(t[i]);
}
all.pb(1); all.pb(1e9);
sort(all.begin(), all.end());
all.resize(unique(all.begin(), all.end())-all.begin());
sw[0]++;
sw[all.size()-1]--;
adj[all.size()-1].pb(0);
for(int i = 0; i< n; i++)
{
int ss = lower_bound(all.begin(), all.end(), s[i])-all.begin();
int tt = lower_bound(all.begin(), all.end(), t[i])-all.begin();
sw[ss]--;
sw[tt]++;
adj[ss].pb(tt);
}
int run = 0;
for(int i = 0; i< (int) all.size(); i++)
{
if(run> 0 && i)
{
adj[i-1].pb(i);
}
run += sw[i];
if(run< 0) return 12345678;
}
memset(col, 0, sizeof col);
ff(0);
for(int i = 0; i< (int) all.size(); i++) if(!col[i]) return 12345678;
return 0;
}
