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epee::misc_utils::median improved

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sowle 2023-12-27 14:06:23 +01:00
parent ee3570b6dd
commit 55bac25b8c
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1 changed files with 12 additions and 13 deletions
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25
contrib/epee/include/misc_language.h
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@ -292,26 +292,25 @@ namespace misc_utils
/************************************************************************/
/* */
/************************************************************************/
template<class type_vec_type>
type_vec_type median(std::vector<type_vec_type> &v)
template<typename container_t>
typename container_t::value_type median(container_t &v)
{
//CRITICAL_REGION_LOCAL(m_lock);
container_t::value_type median{};
if(v.empty())
return boost::value_initialized<type_vec_type>();
return median;
if(v.size() == 1)
return v[0];
size_t n = (v.size()) / 2;
std::sort(v.begin(), v.end());
//nth_element(v.begin(), v.begin()+n-1, v.end());
if(v.size()%2)
{//1, 3, 5...
return v[n];
}else
{//2, 4, 6...
return (v[n-1] + v[n])/2;
auto median_it = v.begin() + v.size() / 2;
std::nth_element(v.begin(), median_it, v.end());
median = *median_it;
if (v.size() % 2 == 0)
{
auto max_it = std::max_element(v.begin(), median_it); // it's garanteed that after nth_element() the necessary element is in this interval
median = (median + *max_it) / 2; // average of [size/2-1] and [size/2] elements
}
return median;
}
/************************************************************************/