#include "railroad.h"
#include <iostream>
#include <vector>
#include <algorithm>
#include <random>
#include <set>
#include <map>
#include <queue>
#include <cstring>
#include <cmath>
#include <bitset>
#include <iomanip>
#include <functional>
using namespace std;
template<typename T> void uin(T &a, T b) {
if (b < a) a = b;
}
#define all(v) v.begin(), v.end()
const long long INF = 1e18 + 228;
const int OGO = 1000 * 1000 * 1000 + 228;
const int N = 400 * 1000 + 228;
long long dp[(1 << 17) + 17][16];
int p[N], siz[N];
void init(int n) {
for (int i = 1; i <= n; ++i) {
p[i] = i;
siz[i] = 1;
}
}
int getp(int v) {
if (v == p[v]) return v;
p[v] = getp(p[v]);
return p[v];
}
void join(int u, int v) {
u = getp(u);
v = getp(v);
if (u != v) {
if (siz[u] > siz[v]) swap(u, v);
p[u] = v;
siz[v] += siz[u];
}
}
struct Edge
{
int u, v, w;
Edge() {}
Edge(int _u, int _v, int _w) {
u = _u;
v = _v;
w = _w;
}
};
bool operator<(Edge A, Edge B) {
return A.w < B.w;
}
vector<int> crd;
vector<int> g[N], gr[N];
int pref[N];
bool used[N];
void dfs(int v, int start) {
join(v, start);
used[v] = 1;
for (int to : gr[v]) {
if (!used[to]) {
dfs(to, start);
}
}
}
int Get(int i) {
return lower_bound(all(crd), i) - crd.begin() + 1;
}
void AddEdge(int from, int to) {
from = Get(from);
to = Get(to);
g[from].emplace_back(to);
++pref[from];
--pref[to];
gr[from].emplace_back(to);
gr[to].emplace_back(from);
}
long long plan_roller_coaster(vector<int> s, vector<int> t) {
int n = (int)s.size();
if (n <= -15) {
for (int i = 0; i < (1 << n); ++i) {
for (int j = 0; j < n; ++j) {
dp[i][j] = INF;
}
}
for (int fir = 0; fir < n; ++fir) {
dp[1 << fir][fir] = 0;
}
for (int mask = 0; mask < (1 << n); ++mask) {
for (int last = 0; last < n; ++last) {
if (dp[mask][last] != INF) {
for (int new_last = 0; new_last < n; ++new_last) {
if ((mask >> new_last) & 1) continue;
long long cur = dp[mask][last] + max(0, t[last] - s[new_last]);
uin(dp[mask | (1 << new_last)][new_last], cur);
}
}
}
}
long long answer = INF;
for (int last = 0; last < n; ++last) {
uin(answer, dp[(1 << n) - 1][last]);
}
return answer;
} else {
// subtask 3
crd.clear();
for (int i = 0; i < n; ++i) {
crd.emplace_back(s[i]);
crd.emplace_back(t[i]);
}
crd.emplace_back(OGO);
sort(crd.begin(), crd.end());
crd.erase(unique(crd.begin(), crd.end()), crd.end());
int sz = (int)crd.size();
for (int i = 0; i < n; ++i) {
AddEdge(s[i], t[i]);
}
AddEdge(OGO, 1);
long long answer = 0;
vector< Edge > edges;
for (int i = 1; i < sz; ++i) {
pref[i] += pref[i - 1];
if (pref[i] > 0) {
answer += (long long)pref[i] * (long long)(crd[i] - crd[i - 1]);
gr[i].emplace_back(i + 1);
gr[i + 1].emplace_back(i);
} else {
if (pref[i] != 0) {
gr[i].emplace_back(i + 1);
gr[i + 1].emplace_back(i);
}
}
edges.emplace_back( i, i + 1, crd[i] - crd[i - 1] );
}
sort(all(edges));
int comps = 0;
init(sz);
for (int i = 1; i <= sz; ++i) {
if (!used[i]) {
dfs(i, i);
}
}
for (auto e : edges) {
int u = e.u, v = e.v, w = e.w;
if (getp(u) != getp(v)) {
answer += w;
join(u, v);
}
}
return answer;
}
return 0;
}
