Submission #681384

#	Time	Username	Problem	Language	Result	Execution time	Memory
681384		YENGOYAN	A Difficult(y) Choice (BOI21_books)	C++17	20 / 100	160 ms	976 KiB

books

#include <bits/stdc++.h>

#include "books.h"

using namespace std;
using ll = long long;
//
// --- 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.
//

void solve(int n, int k, long long a, int s) {
    // TODO implement this function
    vector<long long> vec(n);
    long long sm = 0;
    vec[0] = skim(1);
    sm += vec[0];
    if (vec[0] * k > 2 * a) {
        impossible();
        return;
    }
    vec[n - 1] = skim(n);
    if (vec[n - 1] * k < a) {
        impossible();
        return;
    }
    for (int i = 1; i < k - 1; ++i) {
        vec[i] = skim(i + 1), sm += vec[i];
        if (vec[0] * k > 2 * a) break;
    }
    int l = k - 2, r = n - 1;
    while (l + 1 < r) {
        int m = (l + r) / 2;
        long long b = vec[m];
        if (!b) b = skim(m + 1);
        vec[m] = b;
        if (sm + b >= a) r = m;
        else l = m;
    }
    if (sm + vec[r] > 2 * a || sm + vec[r] < a) {
        for (int i = 0; i <= r; ++i) {
            if (!vec[i]) vec[i] = skim(i + 1);
        }
        sm = 0;
        for (int i = 0; i < k; ++i) sm += vec[i];
        if (sm >= a && sm <= 2 * a) {
            vector<int> ans;
            for (int i = 1; i <= k; ++i) ans.push_back(i);
            answer(ans);
            return;
        }
        for (int i = 1; i + k - 1 <= r; ++i) {
            sm -= vec[i - 1];
            sm += vec[i + k - 1];
            if (sm >= a && sm <= 2 * a) {
                vector<int> ans;
                for (int j = i + 1; j <= i + k; ++j) ans.push_back(j);
                answer(ans);
                return;
            }
        }
        impossible();
    }
    vector<int> ans;
    for (int i = 1; i <= k - 1; ++i) ans.push_back(i);
    ans.push_back(r + 1);
    answer(ans);
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20