Submission #1195598

#	Time	Username	Problem	Language	Result	Execution time	Memory
1195598		anmattroi	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	0 ms	440 KiB

books

#include "books.h"
#include <bits/stdc++.h>

using namespace std;


int64_t cached[100005];

set<int> _s;

long long get(int x) {
    _s.insert(x);
    return cached[x] ? cached[x] : cached[x] = skim(x);
}

void solve(int N, int K, long long A, int S) {
    int64_t SUM = 0;
    for (int i = 1; i <= K; i++) SUM += get(i);
    if (1) {
        int64_t O = SUM - get(K);
        int lo = K-1, hi = N+1;
        while (hi - lo > 1) {
            int mid = (lo + hi) >> 1;
            if (!_s.empty()) {
                auto it = _s.upper_bound(lo);
                if (it != _s.end() && *it < hi) mid = *it;
            }
            int64_t T = get(mid) + O;
            if (A <= T && T <= 2*A) {
                vector<int> ans;
                for (int i = 1; i < K; i++) ans.emplace_back(i);
                ans.emplace_back(mid);
                answer(ans);
                return;
            }
            if (get(mid) >= A) hi = mid;
            else lo = mid;
        }
        N = hi-1;
    }
    if (N < K) {
        impossible();
        return;
    }
    if (A <= SUM && SUM <= 2*A) {
        vector<int> ans;
        for (int i = 1; i <= K; i++) ans.emplace_back(i);
        answer(ans);
        return;
    }
    if (SUM > 2 * A) {
        impossible();
        return;
    }
    for (int i = K; i >= 1; i--) {
        SUM -= get(i);
        SUM += get(N-(K-i+1)+1);
        if (SUM >= A) {
            SUM -= get(N-(K-i+1)+1);
            int lo = i, hi = N-(K-i+1)+2;
            while (hi - lo > 1) {
                int mid = (lo + hi) >> 1;
                if (!_s.empty()) {
                    auto it = _s.upper_bound(lo);
                    if (it != _s.end() && *it < hi) mid = *it;
                }
                int64_t T = SUM + get(mid);
                if (A <= T && T <= 2*A) {
                    vector<int> ans;
                    for (int p = 1; p < i; p++) ans.emplace_back(p);
                    ans.emplace_back(mid);
                    for (int p = N-(K-i)+1; p <= N; p++) ans.emplace_back(p);
                    answer(ans);
                    return;
                }
                if (T >= A) hi = mid;
                else lo = mid;
            }
            assert(false);
        }
    }
    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