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## Function template pdqsort

boost::sort::pdqsort — Generic sort algorithm using random access iterators and a user-defined comparison operator.

## Synopsis

    // In header: <boost/sort/pdqsort/pdqsort.hpp>

    template<typename Iter, typename Compare>
      void pdqsort(Iter first, Iter last, Compare comp);

## Description

`pdqsort` is a fast generic sorting algorithm that is similar in concept to introsort but runs faster on certain patterns. `pdqsort` is in-place, unstable, deterministic, has a worst case runtime of O(N * lg(N)) and a best case of O(N). Even without patterns, the quicksort has been very efficiently implemented, and `pdqsort` runs 1-5% faster than GCC 6.2's `std::sort`. If the type being sorted is `std::is_arithmetic` and Compare is `std::less` or `std::greater` this function will automatically use `pdqsort_branchless` for far greater speedups.

| Warning
Invalid arguments cause undefined behaviour.

| Warning
Throwing an exception may cause data loss.

Parameters:

`comp` | A binary functor that returns whether the first element passed to it should go before the second in order.
`first` | Iterator pointer to first element.
`last` | Iterator pointing to one beyond the end of data.

Requires: | [`first`, `last`) is a valid range.
Requires: | `RandomAccessIter` `value_type` is MoveAssignable
Requires: | `RandomAccessIter` `value_type` is MoveConstructible
Requires: | `RandomAccessIter` `value_type` is LessThanComparable
Postconditions: | The elements in the range [`first`, `last`) are sorted in ascending order.
Returns: | `void`.
Throws: | std::exception Propagates exceptions if any of the element comparisons, the element swaps (or moves), functors, or any operations on iterators throw.