#include "railroad.h"
#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
#define all(x) (x).begin(), (x).end()
#define debug(x) cerr << #x << ": " << x << endl;
#define sep ' '
const ll MAXN = 3e6 + 10;
ll f[MAXN], n, m;
vector<ll> comp_vec;
inline int ind(ll x) {
return lower_bound(all(comp_vec), x) - comp_vec.begin() + 1;
}
ll plan_roller_coaster(vector<int> s, vector<int> t) {
n = s.size();
for (int i = 0; i < n; i++)
comp_vec.push_back(s[i]), comp_vec.push_back(t[i]);
sort(all(comp_vec));
m = comp_vec.size();
multiset<int> st;
for (int i = 0; i < n; i++)
f[ind(s[i])]++, f[ind(t[i])]--;
for (int i = 1; i <= m; i++) {
for (int j = 0; j < f[i]; j++)
st.insert(i);
}
ll ans = 0, mx = 0;
for (int i = 1; i <= m; i++) {
while (f[i] < 0) {
auto it = st.lower_bound(i);
if (it != st.end()) st.erase(it);
else {
it = prev(it);
ll val = comp_vec[i - 1] - comp_vec[*it - 1];
ans += val;
mx = max(mx, val);
}
f[i]++;
}
}
return ans - mx;
}
