Submission #418379

#	Time	Username	Problem	Language	Result	Execution time	Memory
418379		johutha	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	4 ms	972 KiB

books

#include <vector>
#include <iostream>
#include <algorithm>
 
#include "books.h"
 
using namespace std;
//
// --- 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.
//
 
vector<long long> vals;
 
long long skim2(int x)
{
    while(x < 0 || x >= vals.size()){}
    if(vals[x] == 0) vals[x] = skim(x + 1);
    return vals[x];
}
 
void solve(int N, int K, long long A, int S) 
{
    vals.assign(N, 0ll);
    
    vector<long long> lowest(K);
    long long losum = 0;    
    for(int i = 0; i < K; i ++)
    {
        lowest[i] = skim2(i);
        losum += lowest[i];
    }
 
    vector<int> ansvec(K);
    for(int i = 0; i < K; i ++) ansvec[i] = i + 1;
 
    if(losum > 2 * A) impossible();
    else if(losum >= A) answer(ansvec);
 
    int lo = 0, hi = N;
    while(lo + 1 < hi)
    {
        int m = (lo + hi) / 2;
        if(skim2(m) < A) lo = m;
        else hi = m;
    }
 
    if(hi < N && losum - lowest[K - 1] + skim2(hi) <= 2 * A)
    {
        ansvec[K - 1] = hi + 1;
        answer(ansvec);
    }
 
    hi --;
    if(hi < K) impossible();
 
    int j = 0;
    while(losum < A && hi > j && j < K)
    {
        losum += skim2(hi) - lowest[j];
        ansvec[j] = hi + 1;
        j ++;
        hi --;
    }
    if(losum < A) impossible();
    else answer(ansvec);
}

Compilation message (stderr)

books.cpp: In function 'long long int skim2(int)':
books.cpp:22:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |     while(x < 0 || x >= vals.size()){}
      |                    ~~^~~~~~~~~~~~~~

• 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