Submission #1265401

#	Time	Username	Problem	Language	Result	Execution time	Memory
1265401		canhnam357	Jakarta Skyscrapers (APIO15_skyscraper)	C++20	100 / 100	828 ms	68424 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    vector<vector<int>> p(n);
    int f, s, z;
    for (int i = 0; i < m; i++) {
        int b, c;
        cin >> b >> c;
        if (i == 0) f = b, s = c;
        if (i == 1) z = b;
        if (c < n) p[b].push_back(c);
    }
    for (int i = 0; i < n; i++) {
        sort(p[i].begin(), p[i].end());
        p[i].erase(unique(p[i].begin(), p[i].end()), p[i].end());
    }
    const int inf = 1e9;
    const int B = 500;
    vector<vector<pair<int, int>>> adj(n);
    for (int i = 0; i < n; i++) {
        for (int j : p[i]) {
            if (j >= B) {
                int pos = i + j;
                while (pos < n) {
                    adj[i].emplace_back(pos, (pos - i) / j);
                    pos += j;
                }
                pos = i - j;
                while (pos >= 0) {
                    adj[i].emplace_back(pos, (i - pos) / j);
                    pos -= j;
                }
            }
        }
        while (!p[i].empty() && p[i].back() >= B) p[i].pop_back();
    }
    vector<vector<int>> d(n, vector<int>(B, inf));
    d[f][0] = 0;
    priority_queue<tuple<int, int, int>> q;
    q.emplace(0, f, 0);
    while (!q.empty()) {
        auto [dis, u, v] = q.top();
        if (u == z) {
            cout << d[u][v];
            return 0;
        }
        q.pop();
        dis = -dis;
        if (dis != d[u][v]) continue;
        if (!v) {
            for (int i : p[u]) {
                if (d[u][i] > d[u][v]) {
                    d[u][i] = d[u][v];
                    q.emplace(-d[u][i], u, i);
                }
            }
            for (auto [c, w] : adj[u]) {
                if (d[c][0] > d[u][v] + w) {
                    d[c][0] = d[u][v] + w;
                    q.emplace(-d[c][0], c, 0);
                }
            }
        }
        else {
            if (d[u][v] < d[u][0]) {
                d[u][0] = d[u][v];
                q.emplace(-d[u][0], u, 0);
            }
            if (u + v < n && d[u + v][v] > d[u][v] + 1) {
                d[u + v][v] = d[u][v] + 1;
                q.emplace(-d[u + v][v], u + v, v);
            }
            if (u - v >= 0 && d[u - v][v] > d[u][v] + 1) {
                d[u - v][v] = d[u][v] + 1;
                q.emplace(-d[u - v][v], u - v, v);
            }
        }
    }
    cout << -1;
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 14 / 14
• Subtask 4: 21 / 21
• Subtask 5: 43 / 43