Submission #879069

#	Time	Username	Problem	Language	Result	Execution time	Memory
879069		Pelmeni	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	100 / 100	615 ms	13136 KiB

skyscraper

#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;
// #define int long long
typedef pair<int, int> T;
const int oo = 1e9 + 7, K = 30;
const int mod = 998244353;

const int S = 1;

void solve() {
    int n, m;
    cin >> n >> m;
    vector<vector<T>> g(n * S + 2);
    auto ch = [&](int v, int j = 0) { return v * S + j; };
    vector<vector<int>> doge(n + 1);
    int start, kon;
    for (int i = 0; i < m; i++) {
        int v, j;
        cin >> v >> j;
        if (i == 0) start = ch(v);
        if (i == 1) kon = ch(v);
        if (j < S) g[ch(v)].emplace_back(ch(v, j), 0);
        else doge[v].emplace_back(j);
    }

    vector<int> dist(n * S + 2, oo);
    set<T> s;
    s.insert({0, start});
    dist[start] = 0;
    while ((int) s.size()) {
        auto [d, v] = *s.begin();
        s.erase(s.begin());
        if (dist[v] < d) continue;
        auto popraw = [&](int what, int from, int c) {
            if (dist[what] > dist[from] + c) {
                dist[what] = dist[from] + c;
                s.insert({dist[what], what});
            }
        };
        if (v % S == 0) {
            int vv = v / S;
            for (auto j : doge[vv]) {
                for (int u = vv - j, k = 1; u >= 0; u -= j, k++) {
                    popraw(ch(u), v, k);
                }
                for (int u = vv + j, k = 1; u < n; u += j, k++) {
                    popraw(ch(u), v, k);
                }
            }
        }
        //jakies inne losowe
        for (auto [x, c] : g[v]) {
            popraw(x, v, c);
        }
        //krotkie skoki
        int j = v % S;
        if (j != 0) {
            int pos = v - v % S;
            popraw(pos, v, 0);
            int u = pos / S;
            if (u >= j) {
                popraw(ch(u - j, j), v, 1);
            }
            if (u + j < n) {
                popraw(ch(u + j, j), v, 1);
            }
        }
    }
    int ans = dist[kon];
    if (ans == oo) ans = -1;
    cout << ans << "\n";
}

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int t = 1;
    //cin >> t;
    while (t--) solve();

    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'void solve()':
skyscraper.cpp:70:23: warning: 'kon' may be used uninitialized in this function [-Wmaybe-uninitialized]
   70 |     int ans = dist[kon];
      |                       ^

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