#include <bits/stdc++.h>
using namespace std;
#define int long long
vector<int> nxt;
int parent(int u) { return nxt[u] != -1 ? nxt[u] = parent(nxt[u]) : u; }
bool unite(int u, int v) {
u = parent(u); v = parent(v);
if (u == v) return false;
nxt[v] = u; return true;
}
ll plan_roller_coaster(vector<int> s, vector<int> t) {
s.push_back(inf); t.push_back(1); int n = s.size();
vector<int> p = s; p.insert(p.end(), t.begin(), t.end());
sort(p.begin()); p.erase(unique(p.begin(), p.end()), p.end());
int m = p.size(); nxt.resize(m, -1);
vector<int> b(m--);
for(int i = 0; i < n; i++) {
int l = lower_bound(p.begin(), p.end(), s[i]) - p.begin(), r = lower_bound(p.begin(), p.end(), t[i]) - p.begin();
unite(l, r); ++b[l]; --b[r];
}
for(int i = 0; i < m; i++) b[i + 1] += b[i];
vector<pair<int, int>> e; ll ans = 0;
for(int i = 0; i < m; i++) {
ll d = p[i + 1] - p[i];
if (b[i]) {
unite(i, i + 1);
if (b[i] > 0) ans += b[i] * d;
} else e.push_back(d, i);
}
sort(e.begin(), e.end());
for (auto u : e) if (unite(u.second, u.second + 1)) ans += u.first;
return ans;
}
Compilation message
railroad.cpp:13:1: error: 'll' does not name a type
13 | ll plan_roller_coaster(vector<int> s, vector<int> t) {
| ^~
