Submission #948962

#	Time	Username	Problem	Language	Result	Execution time	Memory
948962		vladilius	Bitaro's travel (JOI23_travel)	C++17	0 / 100	3085 ms	76776 KiB

travel

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int ll
 
vector<vector<int>> sp1, sp2;
vector<int> lg;
 
int get1(int l, int r){
    int k = lg[r - l + 1];
    return max(sp1[l][k], sp1[r - (1 << k) + 1][k]);
}
 
int get2(int l, int r){
    int k = lg[r - l + 1];
    return min(sp2[l][k], sp2[r - (1 << k) + 1][k]);
}
 
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    int n; cin>>n;
    vector<int> x(n + 2);
    for (int i = 1; i <= n; i++){
        cin>>x[i];
    }
    x[0] = x[1];
    x[n + 1] = x[n];
    int q; cin>>q;
    vector<int> :: iterator it;
    auto left = [&](int k) -> int{
        if (k == x[n]) return n;
        it = upper_bound(x.begin() + 1, x.end(), k);
        return (int) (prev(it) - x.begin());
    };
    auto right = [&](int k) -> int{
        it = lower_bound(x.begin() + 1, x.end(), k);
        return (int) (it - x.begin());
    };
    
    lg.resize(n + 1);
    for (int i = 2; i <= n; i++){
        lg[i] = lg[i / 2] + 1;
    }
    
    sp1.resize(n + 1);
    sp2.resize(n + 1);
    for (int i = 1; i <= n; i++){
        sp1[i].resize(lg[n] + 1);
        sp2[i].resize(lg[n] + 1);
    }
    for (int i = 1; i <= n; i++){
        sp1[i][0] = 2 * x[i] - x[i - 1];
        sp2[i][0] = 2 * x[i] - x[i + 1];
    }
    for (int j = 1; j <= lg[n]; j++){
        for (int i = 1; i + (1 << j) <= n + 1; i++){
            sp1[i][j] = max(sp1[i][j - 1], sp1[i + (1 << (j - 1))][j - 1]);
            sp2[i][j] = min(sp2[i][j - 1], sp2[i + (1 << (j - 1))][j - 1]);
        }
    }
    
    while (q--){
        int s; cin>>s;
        ll out = 0;
        int i = left(s), j = right(s);
        if (i < 2){
            cout<<x[n] - s<<"\n";
            continue;
        }
        if (j >= n){
            cout<<(s - x[1])<<"\n";
            continue;
        }
        if (s - x[i] <= x[j] - s){
            out += (s - x[i]);
            s = x[i];
            j = i;
        }
        else {
            out += (x[j] - s);
            s = x[j];
            i = j;
        }
        while (i > 1 || j < n){
            if (i == 1){
                out += (x[n] - s);
                break;
            }
            if (j == n){
                out += (s - x[1]);
                break;
            }
            int d1 = s - x[i - 1], d2 = x[j + 1] - s;
            if (d1 <= d2){
                if (get1(2, i) <= x[j + 1]){
                    out += (s - x[1]);
                    s = x[1];
                    i = 1;
                    continue;
                }
                
                // max(k < i): x[k + 1] - x[k] > x[j + 1] - x[k + 1]
                // <-> 2 * x[k + 1] - x[k] > x[j + 1]
                // <-> sp1[k + 1] > x[j + 1]
                // sp1[k + 1][0], ... sp1[i][0]
                
                int l = 1, r = i - 1;
                while (l + 1 < r){
                    int m = (l + r) / 2;
                    if (get1(m + 1, i) > x[j + 1]){
                        l = m;
                    }
                    else {
                        r = m - 1;
                    }
                }
                while (r > 1 && get1(r + 1, i) <= x[j + 1]) r--;
                r++;
                out += (s - x[r]);
                s = x[r];
                i = r;
            }
            else {
                if (get2(j + 1, n - 1) > x[i - 1]){
                    out += (x[n] - s);
                    s = x[n];
                    j = n;
                    continue;
                }
                
                // min(k > j): x[k + 1] - x[k] >= x[k] - x[i - 1]
                // <-> 2 * x[k] - x[k + 1] <= x[i - 1]
                // <-> sp2[k][0] <= x[i - 1]
                // sp2[j + 1][0], ... sp2[k][0]
                
                int l = j + 1, r = n - 1;
                while (l + 1 < r){
                    int m = (l + r) / 2;
                    if (get2(j + 1, m) <= x[i - 1]){
                        r = m;
                    }
                    else {
                        l = m + 1;
                    }
                }
                while (l <= n && get2(j + 1, l) > x[i - 1]) l++;
                l--;
                out += (x[l] - s);
                s = x[l];
                j = l;
            }
        }
        cout<<out<<"\n";
    }
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 55