Submission #162248

#	Time	Username	Problem	Language	Result	Execution time	Memory
162248		rama_pang	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	100 / 100	813 ms	63076 KiB

skyscraper

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

int N, M;
vector<vector<pair<int, int>>> G; // first = destination, second = cost
vector<vector<int>> building;

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> N >> M;

    G.resize(N);
    building.resize(N);

    int start, end, p;
    cin >> start >> p;  building[start].emplace_back(p);
    cin >> end >> p;    building[end].emplace_back(p);

    for (int i = 2; i < M; i++) {
        int b, p;
        cin >> b >> p;
        building[b].emplace_back(p);
    }

    for (auto &n : building) {
        sort(n.begin(), n.end());
        n.resize(unique(n.begin(), n.end()) - n.begin());
    }
        

    /* Build Graph */
    for (int i = 0; i < N; i++) {
        for (auto p : building[i]) {

            for (int step = 1; i + step * p < N; step++) { // forward
                G[i].emplace_back(i + step * p, step);
                if (binary_search(building[i + step * p].begin(), building[i + step * p].end(), p)) break;
            }

            for (int step = 1; i - step * p >= 0; step++) { // backward
                G[i].emplace_back(i - step * p, step);
                if (binary_search(building[i - step * p].begin(), building[i - step * p].end(), p)) break;
            }

        }
    }

    for (auto &n : G) {
        sort(n.begin(), n.end());
        n.resize(unique(n.begin(), n.end()) - n.begin());
    }

    /* Dijkstra on created graph */
    int ans = INT_MAX;

    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
    pq.emplace(0, start);
    vector<int> dist(N, INT_MAX);
    dist[start] = 0;

    while (!pq.empty()) {
        int n = pq.top().second, d = pq.top().first;
        pq.pop();

        if (dist[n] != d) 
            continue;

        if (n == end) {
            ans = d;
            break;
        }
        
        for (auto v : G[n]) {
            if (dist[v.first] == INT_MAX || dist[v.first] > d + v.second) {
                dist[v.first] = d + v.second;
                pq.emplace(dist[v.first], v.first);
            }
        }
    }

    if (ans == INT_MAX) 
        ans = -1;

    cout << ans << "\n";

    return 0;
}

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