Submission #1110869

#	Time	Username	Problem	Language	Result	Execution time	Memory
1110869		vjudge1	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	100 / 100	240 ms	51260 KiB

skyscraper

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

#define ll long long
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)

template <class X, class Y>
    bool minimize(X &x, Y y) {
        if (x > y) return x = y, true;
        else return false;
    }

int n, m;

const ll INF = (ll) 1e18 + 7;

#define ii pair <long long, int>

#define MAX 50'005
vector <ii> adj[MAX + 2];
int b[MAX + 2], p[MAX + 2];
ll dist[MAX + 2];
set <int> jump[MAX + 2], go[MAX + 2];

void Dijkstra(int s) {
    priority_queue <ii, vector <ii>, greater <ii>> q;
    FOR(i, 1, n) dist[i] = INF;
    dist[s] = 0;
    q.push({0, s});

    while (!q.empty()) {
        ll cost = q.top().first;
        int u = q.top().second;
        q.pop();
        if (cost > dist[u]) continue;

        if (u == b[2]) return void(cout << cost);

        for (auto it : adj[u]) {
            int v = it.first, w = it.second;
            if (minimize(dist[v], dist[u] + w)) {
                q.push({dist[v], v});
            }
        }
    }

    cout << -1;
}

void add_edge(int u, int v, int w) {
    adj[u].push_back({v, w});
}

bool used[MAX + 2];

int main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    #define task "sky"
    if (fopen(task".inp","r")) {
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    cin >> n >> m;
    memset(used, false, sizeof(used));
    FOR(i, 1, m) {
        cin >> b[i] >> p[i];
        ++b[i];
        used[b[i]] = true;
        jump[b[i]].insert(p[i]);
    }

    FOR(i, 1, n) {
        if (!used[i]) continue;
        for (int x : jump[i]) {
            int j = x + i, cur = 1;
            while (j <= n) {
                if (used[j]) {
                    add_edge(i, j, cur);
                    if (go[j].find(x) != go[j].end()) break;
                    else go[j].insert(x);
                }
                j += x;
                ++cur;
            }
        }
    }


    FOR(i, 1, n) {
        if (!used[i]) continue;
        for (int x : jump[i]) {
            int j = i - x, cur = 1;
            while (j >= 1) {
                if (used[j]) {
                    add_edge(i, j, cur);
                    if (go[j].find(x) != go[j].end()) break;
                    else go[j].insert(x);
                }
                j -= x;
                ++cur;
            }
        }
    }

    Dijkstra(b[1]);

    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:61:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:62:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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