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https://github.com/bolero-MURAKAMI/Sprout.git
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102 lines
3.2 KiB
C++
102 lines
3.2 KiB
C++
#ifndef SPROUT_ALGORITHM_MAX_ELEMENT_HPP
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#define SPROUT_ALGORITHM_MAX_ELEMENT_HPP
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#include <iterator>
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#include <sprout/config.hpp>
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#include <sprout/iterator/operation.hpp>
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#include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
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#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
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namespace sprout {
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namespace detail {
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template<typename InputIterator, typename Compare>
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inline SPROUT_CONSTEXPR InputIterator
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iter_max(InputIterator a, InputIterator b, Compare comp) {
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return comp(*a, *b) ? b : a;
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}
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template<typename RandomAccessIterator, typename Compare>
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inline SPROUT_CONSTEXPR RandomAccessIterator
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max_element_impl_ra(
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RandomAccessIterator first, RandomAccessIterator last, Compare comp,
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typename std::iterator_traits<RandomAccessIterator>::difference_type pivot
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)
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{
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return pivot == 0 ? first
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: sprout::detail::iter_max(
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sprout::detail::max_element_impl_ra(
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first, sprout::next(first, pivot), comp,
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pivot / 2
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),
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sprout::detail::max_element_impl_ra(
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sprout::next(first, pivot), last, comp,
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(NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) - pivot) / 2
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),
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comp
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)
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;
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}
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template<typename RandomAccessIterator, typename Compare>
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inline SPROUT_CONSTEXPR RandomAccessIterator
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max_element(
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RandomAccessIterator first, RandomAccessIterator last, Compare comp,
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std::random_access_iterator_tag*
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)
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{
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return first == last ? last
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: sprout::detail::max_element_impl_ra(
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first, last, comp,
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NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2
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)
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;
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}
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// Copyright (C) 2011 RiSK (sscrisk)
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template<typename ForwardIterator, typename Compare>
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inline SPROUT_CONSTEXPR ForwardIterator
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max_element_impl(
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ForwardIterator first, ForwardIterator last, Compare comp,
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ForwardIterator found
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)
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{
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return first == last ? found
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: sprout::detail::max_element_impl(sprout::next(first), last, comp, sprout::detail::iter_max(found, first, comp))
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;
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}
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template<typename ForwardIterator, typename Compare>
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inline SPROUT_CONSTEXPR ForwardIterator
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max_element(
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ForwardIterator first, ForwardIterator last, Compare comp,
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void*
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)
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{
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return first == last ? last
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: sprout::detail::max_element_impl(sprout::next(first), last, comp, first)
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;
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}
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} // namespace detail
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// 25.4.7 Minimum and maximum
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//
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// recursion depth:
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// [first, last) is RandomAccessIterator -> O(log N)
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// otherwise -> O(N)
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//
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template<typename ForwardIterator, typename Compare>
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inline SPROUT_CONSTEXPR ForwardIterator
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max_element(ForwardIterator first, ForwardIterator last, Compare comp) {
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typedef typename std::iterator_traits<ForwardIterator>::iterator_category* category;
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return sprout::detail::max_element(first, last, comp, category());
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}
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template<typename ForwardIterator>
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inline SPROUT_CONSTEXPR ForwardIterator
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max_element(ForwardIterator first, ForwardIterator last) {
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return sprout::max_element(
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first, last,
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NS_SSCRISK_CEL_OR_SPROUT::less<typename std::iterator_traits<ForwardIterator>::value_type>()
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);
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_ALGORITHM_MAX_ELEMENT_HPP
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