Submission #636883

#	Time	Username	Problem	Language	Result	Execution time	Memory
636883		classic	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	100 / 100	818 ms	29504 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    vector<int> b(m), p(m);
    vector<vector<int>> doge(n + 1);
    for (int i = 0; i < m; i++) {
        cin >> b[i] >> p[i];
        doge[b[i]].emplace_back(i);
    }
    priority_queue<pair<int, pair<int, int>>, vector<pair<int, pair<int, int>>>, greater<pair<int, pair<int, int>>>> pq;
    pq.push({0, {b[0], 0}});
    vector<vector<int>> dist(n, vector<int>(200, 1e9));
    dist[b[0]][0] = 0;
    int limit = (int)sqrt(n);
    int res = 1e9;
    while (!pq.empty()) {
        pair<int, pair<int, int>> cur = pq.top();
        pq.pop();
        int du = cur.first;
        int u = cur.second.first;
        if (u == b[1]) {
            res = min(res, du);
        }
        int pu = cur.second.second;
        if (pu == 0) {
            for (int id : doge[u]) {
                if (p[id] <= limit) { // nsqrt(n)
                    if (dist[u][p[id]] > du) {
                        dist[u][p[id]] = du;
                        pq.push({du, {u, p[id]}});
                    }
                } else { // msqrt(n)
                    int pv = p[id];
                    for (int j = 1; u - j * pv >= 0; j++) {
                        int v = u - j * pv;
                        int dv = du + j;
                        if (dist[v][0] > dv) {
                            dist[v][0] = dv;
                            pq.push({dv, {v, 0}});
                        }
                    }
                    for (int j = 1; u + j * pv < n; j++) {
                        int v = u + j * pv;
                        int dv = du + j;
                        if (dist[v][0] > dv) {
                            dist[v][0] = dv;
                            pq.push({dv, {v, 0}});
                        }
                    }
                }
            }
        } else {
            if (dist[u][0] > du) { // nsqrt(n)
                dist[u][0] = du;
                pq.push({dist[u][0], {u, 0}});
            }
            // 2nsqrt(n)
            if (u + pu < n && dist[u + pu][pu] > dist[u][pu] + 1) {
                int dv = dist[u][pu] + 1;
                int v = u + pu;
                dist[v][pu] = dist[u][pu] + 1;
                pq.push({dv, {v, pu}});
            }
            if (u - pu >= 0 && dist[u - pu][pu] > dist[u][pu] + 1) {
                int dv = dist[u][pu] + 1;
                int v = u - pu;
                dist[v][pu] = dist[u][pu] + 1;
                pq.push({dv, {v, pu}});
            }
        }
    }
    cout << (res == 1e9 ? -1 : res);
    return 0;
}

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