Submission #890919

#	Time	Username	Problem	Language	Result	Execution time	Memory
890919		vjudge1	Bitaro's travel (JOI23_travel)	C++17	100 / 100	344 ms	75356 KiB

travel

#include <bits/stdc++.h>

using namespace std;

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

using i64 = long long;

template <class F, class _S>
bool chmin(F &u, const _S &v){
    bool flag = false;
    if ( u > v ){
        u = v; flag |= true;
    }
    return flag;
}

template <class F, class _S>
bool chmax(F &u, const _S &v){
    bool flag = false;
    if ( u < v ){
        u = v; flag |= true;
    }
    return flag;
}

struct Sp{
    vector <vector<int>> T;
    int _s;
    Sp(auto &a, int s){
        _s = s;
        T.resize(20);
        int n = a.size();
        for ( auto &x: T ){
            x.resize(n);
        }
        T[0] = a;
        for ( auto &u: T[0] ) u *= _s;
        for ( int i = 1; i < 20; i++ ){
            int k = 1 << i - 1;
            for ( int j = 0; j < n; j++ ){
                T[i][j] = min(T[i - 1][j], T[i - 1][min(n - 1, j + k)]);
            }
        }
    }
    int get(int l, int r){
        int lg = __lg(r - l + 1), k = 1 << lg;
        return min(T[lg][l], T[lg][r - k + 1]) * _s;
    }
};

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

    int n; cin >> n;
    vector <int> X(n);
    for ( auto &u: X ) cin >> u;
    int q; cin >> q;
    vector <int> S(q);
    for ( auto &u: S ) cin >> u;
    vector <int> df(n - 1), df2(n - 1);
    for ( int i = 0; i + 1 < n; i++ ){
        df[i] = X[i + 1] * 2 - X[i];
        df2[i] = X[i + 1] - X[i] * 2;
    }
    Sp sp(df, -1), ap(df2, -1);
    for ( auto &xx: S ){
        int it = lower_bound(all(X), xx) - X.begin();
        if ( it - 1 >= 0 && (it == n || X[it] - xx >= xx - X[it - 1]) ) --it;
        int ans = abs(X[it] - xx), l = it - 1, r = it + 1, x = X[it];
        while ( l >= 0 || r < n ){
//            cout << l + 1 << " " << r + 1 << " -> " << x << ", " << ans << ln;
            if ( l < 0 ){
                ans += abs(X.back() - x);
                break;
            } else if ( r >= n ){
                ans += abs(X[0] - x);
                break;
            } else{
                if ( abs(X[l] - x) <= abs(X[r] - x) ){
                    int tl = 0, tr = l;
                    while ( tl + 1 < tr ){
                        int md = (tl + tr) >> 1;
                        if ( sp.get(md, l - 1) - X[l] <= abs(X[r] - x) ){
                            tr = md;
                        } else tl = md;
                    }
                    ans += abs(X[tr] - x);
                    x = X[tr--]; l = tr;
                } else{
                    int tl = r - 1, tr = n - 1;
                    while ( tl + 1 < tr ){
                        int md = (tl + tr) >> 1;
                        if ( ap.get(r, md) + X[r] < abs(X[l] - x) ){
                            tl = md;
                        } else tr = md;
                    } tl++;
                    ans += abs(X[tr] - x);
                    x = X[tr++]; r = tr;
                }
            }
        }
        cout << ans << ln;
    }

    cout << '\n';
}

Compilation message (stderr)

travel.cpp:34:8: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   34 |     Sp(auto &a, int s){
      |        ^~~~
travel.cpp: In instantiation of 'Sp::Sp(auto:23&, long long int) [with auto:23 = std::vector<long long int>]':
travel.cpp:71:17:   required from here
travel.cpp:44:28: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
   44 |             int k = 1 << i - 1;
      |                          ~~^~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 55 / 55