reduce includes' complexity on some inputs

cf. http://melpon.org/wandbox/permlink/mVNO3IDW8aawsRtD
This commit is contained in:
Mitsuru Kariya 2015-03-29 18:12:52 +09:00
parent b51e338b68
commit 9b5a965efd

View file

@ -19,24 +19,29 @@
namespace sprout {
namespace detail {
template<typename RandomAccessIterator1, typename InputIterator2, typename Compare>
inline SPROUT_CONSTEXPR InputIterator2
inline SPROUT_CONSTEXPR sprout::pair<InputIterator2, bool>
includes_impl_ra(
RandomAccessIterator1 first1, RandomAccessIterator1 last1, InputIterator2 first2, InputIterator2 last2, Compare comp,
typename std::iterator_traits<RandomAccessIterator1>::difference_type pivot
RandomAccessIterator1 first1,
sprout::pair<InputIterator2, bool> current,
InputIterator2 last2, Compare comp,
typename std::iterator_traits<RandomAccessIterator1>::difference_type len
)
{
return first2 == last2 ? first2
: pivot == 0 ? (!comp(*first1, *first2) && !comp(*first2, *first1) ? sprout::next(first2) : first2)
typedef sprout::pair<InputIterator2, bool> type;
return current.second || current.first == last2 ? current
: len == 1 ? comp(*current.first, *first1)
? type(current.first, true)
: type(comp(*first1, *current.first) ? current.first : sprout::next(current.first), false)
: sprout::detail::includes_impl_ra(
sprout::next(first1, pivot), last1,
sprout::next(first1, len / 2),
sprout::detail::includes_impl_ra(
first1, sprout::next(first1, pivot),
first2,
first1,
current,
last2, comp,
pivot / 2
len / 2
),
last2, comp,
(sprout::distance(first1, last1) - pivot) / 2
len - len / 2
)
;
}
@ -52,9 +57,11 @@ namespace sprout {
{
return first1 == last1 ? first2 == last2
: sprout::detail::includes_impl_ra(
first1, last1, first2, last2, comp,
sprout::distance(first1, last1) / 2
)
first1,
sprout::pair<InputIterator2, bool>(first2, false),
last2, comp,
sprout::distance(first1, last1)
).first
== last2
;
}
@ -69,15 +76,19 @@ namespace sprout {
{
typedef sprout::pair<InputIterator1, InputIterator2> type;
return current.second == last2 || current.first == last1 ? current
: n == 1 ? !comp(*current.first, *current.second) && !comp(*current.second, *current.first)
? type(sprout::next(current.first), sprout::next(current.second))
: type(sprout::next(current.first), current.second)
: n == 1
? comp(*current.second, *current.first)
? type(last1, current.second)
: type(
sprout::next(current.first),
comp(*current.first, *current.second) ? current.second : sprout::next(current.second)
)
: sprout::detail::includes_impl_1(
sprout::detail::includes_impl_1(
current,
last1, last2, comp, n / 2
),
last1, last2, comp, n - n / 2
last1, last2, comp, n / 2
)
;
}