Submission #657689

#	Time	Username	Problem	Language	Result	Execution time	Memory
657689		Lobo	A Difficult(y) Choice (BOI21_books)	C++17	20 / 100	2 ms	424 KiB

books

#include <bits/stdc++.h>
#include "books.h"
using namespace std;
#define int long long
#define pb push_back
#define mp make_pair
#define fr first
#define sc second
//
// --- 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.
//
const int maxn = 1e5+10;
int n, b[maxn];
int cnt;
int qry(int32_t i) {
    assert(cnt >= 1);
    cnt--;
    if(b[i] == 0) return b[i] = skim(i);
    return b[i];
}
void solve(int32_t N, int32_t k, long long A, int32_t S) {
    cnt = S;
    n = N;
    // TODO implement this function

    // for(int i = 1; i <= n; i++) {
    //     // r-l+1 = k -> l = r-k+1
    //     int r = i;
    //     int l = r-k+1;
    //     if(l < 1) continue;
    //     int sum = 0;
    //     for(int j = l; j <= r; j++) {
    //         sum+= qry(j);
    //         if(sum > 2*A) {
    //             break;
    //         }
    //     }
    //     if(sum >= A && sum <= 2*A) {
    //         vector<int32_t> ans;
    //         for(int j = l; j <= r; j++) {
    //             ans.pb(j);
    //         }
    //         answer(ans);
    //         return;
    //     }
    // }

    int l = k;
    int r = n;
    while(l <= r) {
        int sum = 0;
        int mid = (l+r)/2;
        for(int j = 1; j <= k-1; j++) {
            sum+= qry(j);
            if(sum > 2*A) {
                break;
            }
        }
        if(sum+qry(mid) > 2*A) {
            r = mid-1;
        }
        else if(sum+qry(mid) < A) {
            l = mid+1;
        }
        else {
            vector<int32_t> ans;
            for(int j = 1; j <= k-1; j++) {
                ans.pb(j);
            }
            ans.pb(mid);
            answer(ans);
            return;
        }
    }

    l = k;
    r = n;
    int ansbs = -1;
    while(l <= r) {
        int mid = (l+r)/2;
        int r1 = mid;
        int l1 = r1-k+1;
        if(l1 < 1) continue;
        int sum = 0;
        for(int j = l1; j <= r1; j++) {
            sum+= qry(j);
            if(sum > 2*A) {
                break;
            }
        }
        if(sum > 2*A) {
            r = mid-1;
        }
        else if(sum < A) {
            l = mid+1;
        }
        else {
            vector<int32_t> ans;
            for(int j = l1; j <= r1; j++) {
                ans.pb(j);
            }
            answer(ans);
            return;
        }

    }

    impossible();
}

Compilation message (stderr)

books.cpp: In function 'void solve(int32_t, int32_t, long long int, int32_t)':
books.cpp:84:9: warning: unused variable 'ansbs' [-Wunused-variable]
   84 |     int ansbs = -1;
      |         ^~~~~

• 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