Submission #657942

#	Time	Username	Problem	Language	Result	Execution time	Memory
657942		Lobo	A Difficult(y) Choice (BOI21_books)	C++17	45 / 100	3 ms	416 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;
const int maxv = 2e17+10;
int n, b[maxn];
int cnt;
int qry(int32_t i) {
    if(b[i] == 0) {
        assert(cnt--);
        return b[i] = skim(i);
    }
    return b[i];
}

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

    l = k;
    r = n;
    int cnt2 = 0;
    while(l <= r) {
        int mid = (l+r)/2;
        int r1 = mid;
        int l1 = r1-k+1;
        if(r-l+1 >= k) cnt2++;
        if(l1 < 1) continue;
        if(qrysum(l1,r1) > 2*A) {
            r = mid-1;
        }
        else if(qrysum(l1,r1) < A) {
            l = mid+1;
        }
        else {
            vector<int32_t> ans;
            for(int j = l1; j <= r1; j++) {
                ans.pb(j);
            }
            answer(ans);
            return;
        }

    }
    impossible();
}

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