Submission #414106

#	Time	Username	Problem	Language	Result	Execution time	Memory
414106		KoD	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	19 ms	268 KiB

books

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

using ll = long long;
template <class T> using Vec = std::vector<T>;

void solve(int N, int K, ll A, int S) {
    int ok = N + 1, ng = 0;
    while (ok - ng > 1) {
        const int md = (ok + ng) / 2;
        (skim(md) >= A ? ok : ng) = md;
    }
    Vec<std::pair<ll, int>> cand;
    for (int i = 1; i <= std::min(K, ok - 1); ++i) {
        cand.emplace_back(skim(i), i);
    }
    for (int i = std::max(K + 1, ok - K); i <= ok - 1; ++i) {
        cand.emplace_back(skim(i), i);
    }
    if (ok <= N and (int) cand.size() >= K - 1) {
        const auto val = skim(ok);
        ll sum = 0;
        for (int i = 0; i < K - 1; ++i) {
            sum += cand[i].first;
        }
        if (sum + val <= 2 * A) {
            Vec<int> ans;
            for (int i = 0; i < K - 1; ++i) {
                ans.push_back(cand[i].second);
            }
            ans.push_back(ok);
            answer(ans);
            return;
        }
    }
    for (int set = 0; set < (1 << cand.size()); ++set) {
        if (__builtin_popcount(set) != K) {
            continue;
        }
        ll sum = 0;
        for (int i = 0; i < (int) cand.size(); ++i) {
            if (set >> i & 1) {
                sum += cand[i].first;
            }
        }
        if (A <= sum and sum <= 2 * A) {
            Vec<int> ans;
            for (int i = 0; i < (int) cand.size(); ++i) {
                if (set >> i & 1) {
                    ans.push_back(cand[i].second);
                }
            }
            answer(ans);
            return;
        }
    }
    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