Submission #736279

#	Time	Username	Problem	Language	Result	Execution time	Memory
736279		Alihan_8	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	10 / 100	1 ms	852 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;

#define all(x) x.begin(), x.end()
#define pb push_back
#define ln '\n'
#define int long long

template <class _T>
bool chmin(_T &x, const _T &y){
    bool flag = false;
    if ( x > y ){
        x = y; flag |= true;
    }
    return flag;
}

template <class _T>
bool chmax(_T &x, const _T &y){
    bool flag = false;
    if ( x < y ){
        x = y; flag |= true;
    }
    return flag;
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m; cin >> n >> m;
    vector <int> g[n];
    int st, en;
    for ( int i = 1; i <= m; i++ ){
        int x, y; cin >> x >> y;
        g[x].pb(y);
        if ( i == 1 ) st = x;
        if ( i == 2 ) en = x;
    }
    const int inf = 1e15 + 1, N = 2e3 + 1;
    vector <vector<int>> dis(n, vector <int> (N, inf));
    deque <pair<int,int>> dq;
    for ( auto i: g[st] ){
        dq.pb({st, i});
        dis[0][i] = 0;
    }
    while ( !dq.empty() ){
        auto [x, p] = dq.front();
        dq.pop_front();
        int v = dis[x][p];
        if ( x - p >= 0 and chmin(dis[x - p][p], v + 1) ){
            dq.pb({x - p, p});
        }
        if ( x + p < n and chmin(dis[x + p][p], v + 1) ){
            dq.pb({x + p, p});
        }
        for ( auto to: g[x] ){
            if ( chmin(dis[x][to], v) ){
                dq.push_front({x, to});
            }
        }
    }
    int ans = *min_element(all(dis[en]));
    if ( ans == inf ) ans = -1;
    cout << ans;

    cout << '\n';
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:34:9: warning: 'st' may be used uninitialized in this function [-Wmaybe-uninitialized]
   34 |     int st, en;
      |         ^~
skyscraper.cpp:64:38: warning: 'en' may be used uninitialized in this function [-Wmaybe-uninitialized]
   64 |     int ans = *min_element(all(dis[en]));
      |                                      ^

• Subtask 1: 10 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 43