Submission #730511

#	Time	Username	Problem	Language	Result	Execution time	Memory
730511		nguyentunglam	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	2 ms	432 KiB

books

#include <bits/stdc++.h>

#include "books.h"

using namespace std;
const int N = 1e5 + 10;
long long a[N];
//
// --- Sample implementation for the task books ---
//
// To compile this program with the sample grader, place:
//     books.h books_sample.cpp sample_grader.cpp
// in a single folder and run:
//     g++ books_sample.cpp sample_grader.cpp
// in this folder.
//
long long Skim(int i) {
    if (a[i]) return a[i];
    return a[i] = skim(i);
}

void solve(int n, int k, long long A, int s) {
//    // TODO implement this function
    int l = 1, r = n;
    long long v = 0;
    int p = n + 1;
    while (l <= r) {
        int mid = l + r >> 1;
        long long tmp = Skim(mid);
        if (tmp >= A) {
            v = tmp; p = mid;
            r = mid - 1;
        }
        else l = mid + 1;
    }


    for(int i = 1; i <= k - 1; i++) v += Skim(i);

    vector<int> ret;
    if (p <= n && k - 1 < p && v <= A * 2) {
        for(int i = 1; i <= k - 1; i++) ret.push_back(i);
        ret.push_back(p);
        answer(ret);
    }

    long long cur = 0;
    for(int i = k; i >= 1; i--) {
        ret.push_back(i);
        cur += Skim(i);
        if (cur > A * 2) {
            impossible();
            return;
        }
    }
    if (cur >= A) answer(ret);
    else {
        --p;
        vector<int> add;
        if (p < 0 || p > n) return;
        while (p > k && !ret.empty()) {
            cur = cur - Skim(ret.back()) + Skim(p);
            ret.pop_back();
            add.push_back(p);
            p--;
            if (cur >= A) {
                for(int &j : add) ret.push_back(j);
                answer(ret);
                return;
            }
        }
        impossible();
    }
}

Compilation message (stderr)

books.cpp: In function 'void solve(int, int, long long int, int)':
books.cpp:28:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   28 |         int mid = l + r >> 1;
      |                   ~~^~~

• 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