Submission #863745

#	Time	Username	Problem	Language	Result	Execution time	Memory
863745		TAhmed33	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	1 ms	608 KiB

books

#include <bits/stdc++.h>
#include <books.h>
#pragma GCC optimize ("trapv")
using namespace std;
typedef long long ll;
bool check (ll sum, ll a) {
    return sum >= a && sum <= 2 * a;
}
void solve (int n, int k, ll a, int s) {
    map <int, ll> dd;
    int l = k, r = n;
    for (int i = 1; i < k; i++) dd[i] = skim(i);
    int ans = -1;
    while (l <= r) {
        int mid = (l + r) >> 1;
        if (!dd.count(mid)) dd[mid] = skim(mid);
        if (dd[mid] > a) {
            r = mid - 1; ans = mid;
        } else {
            l = mid + 1;
        }
    }
    ll sum = 0;
    for (int i = 1; i < k; i++) sum += dd[i];
    if (ans != -1) {
        sum += dd[ans];
        if (check(sum, a)) {
            vector <int> t;
            for (int i = 1; i < k; i++) t.push_back(i);
            t.push_back(ans);
            answer(t);
        }
    }
    if (ans == -1) ans = n + 1;
    if (!dd.count(k)) dd[k] = skim(k);
    vector <pair <int, ll>> u;
    for (int i = 1; i <= k; i++) {
        if (!dd.count(i)) dd[i] = skim(i);
        u.push_back({i, dd[i]});
    }
    for (int i = max(1, ans - k); i < ans; i++) {
        if (!dd.count(i)) dd[i] = skim(i);
        u.push_back({i, dd[i]});
    }
    sum = 0;
    for (int i = 0; i < k; i++) sum += u[i].second;
    if (check(sum, a)) {
        vector <int> t;
        for (int i = 0; i < k; i++) t.push_back(u[i].first);
        sort(t.begin(), t.end());
        answer(t);
    }
    for (int i = k; i < (int)u.size(); i++) {
        sum -= u[i - k].second;
        sum += u[i].second;
        if (check(sum, a)) {
            vector <int> t;
            for (int j = i - k + 1; j <= i; j++) {
                t.push_back(u[j].first);
            }
            sort(t.begin(), t.end());
            answer(t);
        }
    }
    impossible();
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 10 / 10
• Subtask 4: 15 / 15
• Subtask 5: 15 / 15
• Subtask 6: 20 / 20
• Subtask 7: 20 / 20