Submission #1189319

#	Time	Username	Problem	Language	Result	Execution time	Memory
1189319		anmattroi	Roller Coaster Railroad (IOI16_railroad)	C++17	100 / 100	426 ms	33160 KiB

railroad

#include "railroad.h"
#include <bits/stdc++.h>
#define fi first
#define se second
#define maxn 200005
using namespace std;
using ii = pair<int, int>;

int par[2*maxn];

struct edge {
    int u, v, l;
    edge() {}
    edge(int _u, int _v, int _l) : u(_u), v(_v), l(_l) {}

    bool operator < (const edge &other) const {
        return l < other.l;
    }
};

vector<edge> edges;

int find_set(int v) {
    return par[v] < 0 ? v : par[v] = find_set(par[v]);
}

void union_set(int u, int v) {
    u = find_set(u); v = find_set(v);
    if (u == v) return;
    if (par[u] < par[v]) swap(u, v);
    par[v] += par[u];
    par[u] = v;
}

long long plan_roller_coaster(vector<int> s, vector<int> t) {
    s.emplace_back(1e9);
    t.emplace_back(1);

    int n = s.size();
    map<int, int> nho;

    for (int i = 0; i < n; i++) {
        ++nho[s[i]];
        --nho[t[i]];
    }
    int last = 0;
    for (auto &i : nho) last = (i.se += last);

    vector<int> a;
    for (int i = 0; i < n; i++) {
        a.emplace_back(s[i]);
        a.emplace_back(t[i]);
    }
    sort(a.begin(), a.end());
    a.erase(unique(a.begin(), a.end()), a.end());

    int m = a.size();

    for (int i = 0; i < m; i++) par[i] = -1;

    for (int i = 0; i < n; i++) {
        int p = lower_bound(a.begin(), a.end(), s[i]) - a.begin(),
            q = lower_bound(a.begin(), a.end(), t[i]) - a.begin();
        union_set(p, q);
    }

    int64_t ans = 0;
    for (auto &i : nho)
        if (i.se > 0) {
            int p = lower_bound(a.begin(), a.end(), i.fi) - a.begin();
            ans += 1LL * (a[p+1] - a[p]) * i.se;
            union_set(p+1, p);
            i.se = 0;
        }

    for (auto [u, v] : nho)
    if (v < 0) {
        int p = lower_bound(a.begin(), a.end(), u) - a.begin();
        union_set(p, p+1);
    }
    for (int i = 0; i < m-1; i++) edges.emplace_back(i, i+1, a[i+1]-a[i]);

    sort(edges.begin(), edges.end());
    for (auto [u, v, l] : edges)
    if (find_set(u) != find_set(v)) {
        union_set(u, v);
        ans += l;
    }
    return ans;
}

Compilation message (stderr)

railroad.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
railroad_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 30 / 30
• Subtask 4: 36 / 36