Submission #657946

#	Time	Username	Problem	Language	Result	Execution time	Memory
657946		Lobo	A Difficult(y) Choice (BOI21_books)	C++17	60 / 100	2 ms	436 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 = 2e18+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;

    int l,r;

    l = 1;
    r = n;
    int p = -1;
    while(l <= r) {
        int mid = (l+r)/2;
        if(qry(mid) >= A) {
            r = mid-1;
            p = mid;
        }
        else {
            l = mid+1;
        }
    }

    if(p != -1) {
        if(p < k) {
            impossible();
            return;
        }
        if(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;
        }

        if(p == k) {
            impossible();
            return;
        }
        n = p-1;
        // n is >= k
    }

    l = 1;
    r = n-k+1;
    while(l <= r) {
        int mid = (l+r)/2;
        if(qrysum(mid,mid+k-1) < A) {
            l = mid+1;
        }
        else if(qrysum(mid,mid+k-1) > 2*A) {
            r = mid-1;
        }
        else {
            vector<int32_t> ans;
            for(int j = mid; j <= mid+k-1; 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: 15 / 15
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20