Submission #954548

#	Time	Username	Problem	Language	Result	Execution time	Memory
954548		boris_mihov	Xoractive (IZhO19_xoractive)	C++17	100 / 100	4 ms	848 KiB

Xoractive

#include "interactive.h"
#include <vector>
#include <map>
#include <set>

const int MAXN = 100 + 10;

std::map <int,int> map;
std::vector <int> query(std::vector <int> v)
{
    std::vector <int> res;
    for (int &i : v) i++;
    std::vector <int> returned = get_pairwise_xor(v);
    for (int i = v.size() ; i < returned.size() ; i += 2)
    {
        res.push_back(returned[i]);
    }

    return res;
}

std::vector <int> guess(int n)
{
    std::vector <int> result(n);
    result[0] = ask(1);

    for (int bit = 0 ; (1 << bit) < n ; ++bit)
    {
        std::vector <int> v;
        for (int i = 1 ; i < n ; ++i)
        {
            if (i & (1 << bit))
            {
                v.push_back(i);
            }
        }

        if (v.empty())
        {
            continue;
        }

        std::vector <int> without = query(v); v.push_back(0);
        std::vector <int> with = query(v);
        std::multiset <int> vals;

        for (const int &val : with)
        {
            vals.insert(val);
        }

        for (const int &val : without)
        {
            vals.erase(vals.find(val));
        }

        int last = -1;
        for (const int &val : vals)
        {
            if (val == last)
            {
                continue;
            }

            map[val ^ result[0]] |= (1 << bit);
            last = val;
        }
    }

    for (const auto &[key, value] : map)
    {
        result[value] = key;
    }

    return result;
}

Compilation message (stderr)

Xoractive.cpp: In function 'std::vector<int> query(std::vector<int>)':
Xoractive.cpp:14:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |     for (int i = v.size() ; i < returned.size() ; i += 2)
      |                             ~~^~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 94 / 94