Submission #433522

#	Time	Username	Problem	Language	Result	Execution time	Memory
433522		Lam_lai_cuoc_doi	Hidden Sequence (info1cup18_hidden)	C++17	100 / 100	10 ms	428 KiB

hidden

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;

constexpr bool typetest = 0;
constexpr int N = 2e2 + 2;

#include "grader.h"

bool Check(int a, int b, int c)
{
    vector<int> ans(a, c);

    while (b--)
        ans.emplace_back(c ^ 1);

    return isSubsequence(ans);
}

vector<int> findSequence(int n)
{
    vector<int> ans;
    int total(0); // number of zero

    // count number of zero
    for (int i = 1; i <= n / 2 + 1; ++i)
    {
        if (!Check(i, 0, 0))
            break;
        total = i;
    }

    if (total == n / 2 + 1)
    {
        total = 0;
        for (int i = 1; i <= n / 2 + 1; ++i)
        {
            if (!Check(i, 0, 1))
                break;
            total = i;
        }
        total = n - total;
    }

    // Cal ans

    /* Let i is the bit 0 now we're considering (It means there are i - 1 filled - bits)
            j is the bit 1 now we're considering (It means there are j - 1 filled - bits)
    
    There are 2 cases:
        
        - if j + (total - i + 1) <= n / 2 + 1, we could check string (j * '1' + (total - i + 1) * '0') because the bit 0 before we don't need to care
        - if j + (total - i + 1) > n / 2 <-> n - j - total + i - 1 < n / 2 <-> i + (n - j - total + 1) <= n / 2 + 1:
                we could checkstring (i * '0' + (n - j - total + 1) * '1')
                because the string before the (i - 1) - 0 bit is defined so it's only necessary to check string after i - 0 bit
    */

    for (int i = 1, j = 1; i <= total; ++i) // the bit 0 now we're considering
    {
        for (; j <= n - total; ++j)
        {
            if (j + (total - i + 1) <= n / 2 + 1 ? !Check(j, total - i + 1, 1) : Check(i, n - total - j + 1, 0))
                break;

            ans.emplace_back(1);
        }
        ans.emplace_back(0);
    }

    while ((int)ans.size() < n)
        ans.emplace_back(1);
    return ans;
}

Compilation message (stderr)

grader.cpp: In function 'int main()':
grader.cpp:28:26: warning: format '%d' expects argument of type 'int', but argument 3 has type 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wformat=]
   28 |     fprintf (fifo_out, "%d\n", ans.size ());
      |                         ~^     ~~~~~~~~~~~
      |                          |              |
      |                          int            std::vector<int>::size_type {aka long unsigned int}
      |                         %ld
grader.cpp:29:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |     for (int i=0; i<ans.size () && i < N; i++)
      |                   ~^~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 80 / 80