Submission #834320

#	Time	Username	Problem	Language	Result	Execution time	Memory
834320		finn__	Counting Mushrooms (IOI20_mushrooms)	C++17	0 / 100	1 ms	332 KiB

mushrooms

#include <bits/stdc++.h>

#include "mushrooms.h"

using namespace std;

constexpr size_t M = 80;

int count_mushrooms(int n)
{
    vector<int> a_indices = {0}, b_indices;

    (use_machine({0, 1}) ? b_indices : a_indices).push_back(1);
    (use_machine({0, 2}) ? b_indices : a_indices).push_back(2);

    int last_known = 2;

    // Search for at least M A or B.
    for (int i = last_known + 1; i + 1 < n; i += 2)
    {
        int x = use_machine({a_indices.size() >= 2 ? a_indices[0] : b_indices[0], i,
                             a_indices.size() >= 2 ? a_indices[1] : b_indices[1], i + 1});
        last_known = i + 1;
        if ((x & 1) ^ (a_indices.size() < 2))
            b_indices.push_back(i + 1);
        else
            a_indices.push_back(i + 1);
        if ((x & 2) ^ (a_indices.size() < 2))
            b_indices.push_back(i);
        else
            a_indices.push_back(i);

        if (a_indices.size() >= M || b_indices.size() >= M)
            break;
    }

    int num_a = a_indices.size();

    {
        for (int i = last_known + 1; i < n;)
        {
            vector<int> &r = a_indices.size() > b_indices.size() ? a_indices : b_indices;
            size_t m = r.size();
            bool flag = a_indices.size() > b_indices.size();
            vector<int> v;
            for (int j = 0; j < m && i + j < n; ++j)
            {
                v.push_back(r[j]);
                v.push_back(i + j);
            }

            int x = use_machine(v);
            num_a += flag ? v.size() / 2 - (x + 1) / 2 : (x + 1) / 2;
            (((x & 1) ^ flag) ? a_indices : b_indices).push_back(min<size_t>(n - 1, i + m - 1));
            i += m;
        }
    }

    return num_a;
}

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:46:31: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
   46 |             for (int j = 0; j < m && i + j < n; ++j)
      |                             ~~^~~

• Subtask 1: 0 / 100