제출 #687341

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
687341		Alcabel	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	1 ms	348 KiB

books

#include <bits/stdc++.h>
#include <books.h>
using namespace std;

void solve(int n, int k, long long a, int s) {
    int l = -1, r = n;
    long long found = -1;
    while (r - l > 1) {
        int m = l + (r - l) / 2;
        long long cur = skim(m + 1);
        if (cur >= a) {
            found = cur;
            r = m;
        } else {
            l = m;
        }
    }
    vector<int> ans(k);
    iota(ans.begin(), ans.end(), 1);
    if (r + 1 <= k - 1) {
        impossible();
        return;
    }
    vector<long long> first(k);
    long long sumFirst = 0;
    for (int i = 0; i < k; ++i) {
        first[i] = skim(i + 1);
        sumFirst += first[i];
    }
    if (r != n && sumFirst - first.back() + found <= 2 * a) {
        ans.back() = r + 1;
        answer(ans);
        return;
    }
    n = r;
    vector<long long> last(k);
    long long sumLast = 0;
    for (int i = n - 1; i >= n - k; --i) {
        last[n - 1 - i] = skim(i + 1);
        sumLast += last[n - 1 - i];
    }
    if (sumFirst >= a && sumFirst <= 2 * a) {
        answer(ans);
        return;
    }
    if (sumLast >= a && sumLast <= 2 * a) {
        iota(ans.begin(), ans.end(), n - k + 1);
        answer(ans);
        return;
    }
    if (sumFirst > 2 * a || sumLast < a) {
        impossible();
        return;
    }
    long long sum = sumFirst;
    iota(ans.begin(), ans.end(), 1);
    for (int i = k - 1; sum < a; --i) {
        assert(i >= 0);
        sum -= first[i];
        sum += last[k - 1 - i];
        ans[i] = n - (k - 1 - i);
    }
    answer(ans);
}

• 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