LoHiSort.cpp

#include <map>
#include <vector>
#include <string>
#include <algorithm>
#include <thread>

#include <future>


#include <iostream>


template<class IT>
void merge_sort_th(IT first, IT last, size_t min_len = 16)
{
    auto len = std::distance(first, last);
    
    if (len < min_len)
    {
        std::sort(first, last);
        return;
    }


    IT halfIt = first + len/2;

    std::thread loSort(merge_sort_th<IT>, first, halfIt, min_len);
    merge_sort_th(halfIt, last, min_len);

    loSort.join();

    std::inplace_merge(first, halfIt, last);
}


int main()
{
    std::vector<int>  a(1001);
    
    for (int i = 0; i < a.size(); ++i)
    {
        a[i] = rand() % 91;
    }
    
    merge_sort_th(a.begin(), a.end());
    
    for (auto elem : a) {
        std::cout << elem << ' ';
    }
    std::cout << std::endl << std::boolalpha << std::is_sorted(a.begin(), a.end());

    return 0;
}