Submission #768912

#	Time	Username	Problem	Language	Result	Execution time	Memory
768912		raysh07	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	100 / 100	172 ms	124448 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define INF (int)1e18
#define f first
#define s second

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

void Solve() 
{
    int n, m; cin >> n >> m;
    
    vector <pair<int, int>> a(m);
    set <int> st[n];
    int target;
    vector <int> d(n, INF);
    priority_queue <pair<int, int>> pq;
    for (int i = 0; i < m; i++){
        cin >> a[i].f >> a[i].s;
        
        if (i == 0) {
            d[a[i].f] = 0;
            pq.push({0, a[i].f});
        }
        if (i != 1) st[a[i].f].insert(a[i].s);
        else target = a[i].f;
    }
    
    vector<vector<pair<int, int>>> adj(n);
    for (int i = 0; i < n; i++){
        for (auto x : st[i]){
            for (int j = 1; ; j++){
                int go = x * j + i;
                if (go >= n || go < 0) break;
                adj[i].push_back({go, j});
                if (st[go].find(x) != st[go].end()) break;
            }
            
            for (int j = 1; ; j++){
                int go = i - x * j;
                if (go < 0 || go >= n) break;
                adj[i].push_back({go, j});
                if (st[go].find(x) != st[go].end()) break;
            }
        }
    }
    
    while (!pq.empty()){
        auto pi = pq.top();
        pq.pop();
        
        int u = pi.second;
        int ds = -pi.first;
        
        if (d[u] != ds) continue;
        
        for (auto [v, w] : adj[u]){
            if (d[v] > d[u] + w){
                d[v] = d[u] + w;
                pq.push({-d[v], v});
            }
        }
    }
  //  cout << target << "\n";
    
    if (d[target] == INF) cout << -1 << "\n";
    else cout << d[target] << "\n";
}

int32_t main() 
{
    auto begin = std::chrono::high_resolution_clock::now();
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
 //   cin >> t;
    for(int i = 1; i <= t; i++) 
    {
        //cout << "Case #" << i << ": ";
        Solve();
    }
    auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'void Solve()':
skyscraper.cpp:67:17: warning: 'target' may be used uninitialized in this function [-Wmaybe-uninitialized]
   67 |     if (d[target] == INF) cout << -1 << "\n";
      |                 ^

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