#include <bits/stdc++.h>
#include "railroad.h"
using namespace std;
typedef long long ll;
const int maxn = 4e5+10;
struct DSU
{
int pai[maxn], peso[maxn];
void init(int n)
{
for (int i = 0; i < n; i++)
pai[i] = i, peso[i] = 1;
}
int Find(int x)
{
if (pai[x] == x) return x;
return pai[x] = Find(pai[x]);
}
void Join(int x, int y)
{
x = Find(x), y = Find(y);
if (x == y) return;
if (peso[x] < peso[y]) swap(x, y);
pai[y] = x, peso[x] += peso[y];
}
} dsu;
struct Edge
{
int u, v, w;
bool operator< (const Edge o)
{
return w < o.w;
}
};
map<int, int> mp;
int back[maxn];
int soma[maxn];
long long plan_roller_coaster(vector<int> s, vector<int> t)
{
s.push_back(1e9); s.push_back(1);
int n = (int) s.size();
for (int i = 0; i < n; i++)
mp[s[i]] = mp[t[i]] = 0;
int aux = 0;
for (auto &x: mp)
{
x.second = aux++;
back[aux-1] = x.second;
}
ll ans = 0;
vector<int> v;
vector<Edge> edge;
dsu.init(aux);
for (int i = 0; i < n; i++)
{
soma[mp[s[i]]]++;
soma[mp[t[i]]]--;
v.push_back(mp[s[i]]);
v.push_back(mp[t[i]]);
dsu.Join(mp[s[i]], mp[t[i]]);
}
for (int i = 0; i < aux; i++)
{
if (i) soma[i] += soma[i-1];
if (soma[i] > 0)
{
dsu.Join(i, i+1);
ans += 1ll*(back[i+1]-back[i])*soma[i];
}
else if (soma[i] < 0) dsu.Join(i, i+1);
if (i < aux-1) edge.push_back({i, i+1, back[i+1]-back[i]});
}
sort(edge.begin(), edge.end());
for (auto pp: edge)
{
int u = pp.u, v = pp.v, w = pp.w;
if (dsu.Find(u) != dsu.Find(v))
{
dsu.Join(u, v);
ans += 1ll*w;
}
}
return ans;
}
