Submission #726855

#	Time	Username	Problem	Language	Result	Execution time	Memory
726855		finn__	A Difficult(y) Choice (BOI21_books)	C++17	100 / 100	2 ms	420 KiB

books

#include <bits/stdc++.h>
#include "books.h"
using namespace std;

constexpr size_t N = 100001;

long long cache[N];

long long query(int i) { return cache[i] ? cache[i] : cache[i] = skim(i); }

void solve(int N, int K, long long A, int S)
{
    int a = 1, b = N;
    while (a < b)
    {
        int mid = (a + b) / 2;
        if (query(mid) <= A)
            a = mid + 1;
        else
            b = mid;
    }
    long long sum = 0;
    for (size_t i = 1; i < K; ++i)
        sum += query(i);
    if (query(a) <= A)
        ++a;
    if (a <= N && query(a) + sum <= 2 * A)
    {
        vector<int> v(K);
        iota(v.begin(), v.begin() + K - 1, 1);
        v.back() = a;
        answer(v);
    }
    sum += query(K);
    if (A <= sum && sum <= 2 * A)
    {
        vector<int> v(K);
        iota(v.begin(), v.end(), 1);
        answer(v);
    }
    if (2 * K >= a)
    {
        for (size_t i = K + 1; i < a; ++i)
        {
            sum -= query(i - K);
            sum += query(i);
            if (A <= sum && sum <= 2 * A)
            {
                vector<int> v;
                iota(v.begin(), v.end(), i - K + 1);
                answer(v);
            }
        }
    }
    else
    {
        for (size_t i = 0; i < K; ++i)
        {
            sum -= query(K - i);
            sum += query(a - K + i);
            if (A <= sum && sum <= 2 * A)
            {
                vector<int> v(K);
                iota(v.begin(), v.begin() + K - i - 1, 1);
                iota(v.begin() + K - i - 1, v.end(), a - K);
                answer(v);
            }
        }
    }
    impossible();
}

Compilation message (stderr)

books.cpp: In function 'void solve(int, int, long long int, int)':
books.cpp:23:26: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   23 |     for (size_t i = 1; i < K; ++i)
      |                        ~~^~~
books.cpp:43:34: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   43 |         for (size_t i = K + 1; i < a; ++i)
      |                                ~~^~~
books.cpp:57:30: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   57 |         for (size_t i = 0; i < K; ++i)
      |                            ~~^~~

• 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