introsort.h

// Copyright (c) 2013 Craig Henderson
// https://github.com/cdmh/sorting_algorithms

#include "sort.h"
#include "introsort.detail.h"
#include <cmath>    // floor, log

namespace cdmh {

// Introsort
//     Worst case performance       O(n log n)
//     Average case performance     O(n log n)
// http://en.wikipedia.org/wiki/Introsort

template<typename It, typename Pred=std::less<typename std::iterator_traits<It>::value_type>>
inline void introsort(It begin, It end, Pred pred=Pred())
{
    if (std::distance(begin, end) > 1)
        detail::introsort(begin, end, pred, (size_t)floor(log(std::distance(begin,end)/log(2.0))));
}

}   // namespace cdmh

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