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fix implementation: search_n

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bolero-MURAKAMI 2012-12-13 18:08:59 +09:00
parent 9b0d1a7933
commit d6914ddd72
3 changed files with 124 additions and 21 deletions
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42
sprout/algorithm/search_n.hpp
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@ -3,33 +3,33 @@
#include <sprout/config.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/iterator/value_iterator.hpp>
#include <sprout/functional/equal_to.hpp>
#include <sprout/algorithm/search.hpp>
namespace sprout {
// Copyright (C) 2011 RiSK (sscrisk)
// 25.2.13 Search
template<typename ForwardIterator, typename Size, typename T>
inline SPROUT_CONSTEXPR ForwardIterator
search_n(ForwardIterator first, ForwardIterator last, Size count, T const& value) {
return first == last || count == 0 ? first
: sprout::next(first) == last && count > 1 ? last
: *first == value
&& sprout::search_n(sprout::next(first), last, count - 1, value) == sprout::next(first)
? first
: sprout::search_n(sprout::next(first), last, count, value)
;
}
//
// recursion depth:
// [first, last) is RandomAccessIterator -> O(log N)
// otherwise -> O(N)
//
template<typename ForwardIterator, typename Size, typename T, typename BinaryPredicate>
inline SPROUT_CONSTEXPR ForwardIterator
search_n(ForwardIterator first, ForwardIterator last, Size count, T const& value, BinaryPredicate pred) {
return first == last || count == 0 ? first
: sprout::next(first) == last && count > 1 ? last
: *first == value
&& sprout::search_n(sprout::next(first), last, count - 1, value, pred) == sprout::next(first)
? first
: sprout::search_n(sprout::next(first), last, count, value, pred)
;
typedef sprout::value_iterator<T const&> iterator;
typedef typename iterator::difference_type difference_type;
return sprout::search(
first, last,
iterator(value, static_cast<difference_type>(count)), iterator(value, 0),
pred
);
}
template<typename ForwardIterator, typename Size, typename T>
inline SPROUT_CONSTEXPR ForwardIterator
search_n(ForwardIterator first, ForwardIterator last, Size count, T const& value) {
return sprout::search_n(first, last, count, value, sprout::equal_to<>());
}
} // namespace sprout