diff --git a/sprout/algorithm/find_end.hpp b/sprout/algorithm/find_end.hpp
index 00519edb..511b3b36 100644
--- a/sprout/algorithm/find_end.hpp
+++ b/sprout/algorithm/find_end.hpp
@@ -16,74 +16,148 @@
 #include <sprout/functional/equal_to.hpp>
 #include <sprout/utility/pair/pair.hpp>
 #include <sprout/detail/algorithm/search_one.hpp>
+#include <sprout/detail/algorithm/search_one_rev.hpp>
 
 namespace sprout {
 	namespace detail {
-		// !!!
-//		template<typename RandomAccessIterator1>
-//		inline SPROUT_CONSTEXPR RandomAccessIterator1
-//		find_end_impl_check_ra(RandomAccessIterator1 first1, RandomAccessIterator1 result, RandomAccessIterator1 searched) {
-//			return searched == first1 ? searched
-//				: result
-//				;
-//		}
-//		template<typename RandomAccessIterator1, typename ForwardIterator2, typename BinaryPredicate>
-//		inline SPROUT_CONSTEXPR RandomAccessIterator1
-//		find_end_impl_ra(
-//			RandomAccessIterator1 first1, RandomAccessIterator1 last1,
-//			ForwardIterator2 first2, ForwardIterator2 last2,
-//			BinaryPredicate pred,
-//			typename std::iterator_traits<RandomAccessIterator1>::difference_type pivot, RandomAccessIterator1 last1_, RandomAccessIterator1 result,
-//			RandomAccessIterator1 searched
-//			)
-//		{
-//			return searched == last1_ ? result
-//				: searched < first1 ? pivot == 0
-//					? sprout::detail::find_end_impl_check_ra(
-//						first1, searched,
-//						sprout::detail::search_one(first1, last1_, first2, last2, pred)
-//						)
-//					: sprout::detail::find_end_impl_ra(
-//						sprout::next(first1, pivot), last1, first2, last2, pred,
-//						(sprout::distance(first1, last1) - pivot) / 2, last1_, searched,
-//						sprout::detail::find_end_impl_ra(
-//							first1, sprout::next(first1, pivot), first2, last2, pred,
-//							pivot / 2, last1_, searched,
-//							first1
-//							)
-//						)
-//				: pivot == 0 ? sprout::detail::search_one(first1, last1_, first2, last2, pred)
-//				: sprout::detail::find_end_impl_ra(
-//					sprout::next(first1, pivot), last1, first2, last2, pred,
-//					(sprout::distance(first1, last1) - pivot) / 2, last1_, result,
-//					sprout::detail::find_end_impl_ra(
-//						first1, sprout::next(first1, pivot), first2, last2, pred,
-//						pivot / 2, last1_, result,
-//						first1
-//						)
-//					)
-//				;
-//		}
-//		template<typename RandomAccessIterator1, typename ForwardIterator2, typename BinaryPredicate>
-//		inline SPROUT_CONSTEXPR typename std::enable_if<
-//			sprout::is_constant_distance_iterator<RandomAccessIterator1>::value,
-//			RandomAccessIterator1
-//		>::type
-//		find_end(
-//			RandomAccessIterator1 first1, RandomAccessIterator1 last1,
-//			ForwardIterator2 first2, ForwardIterator2 last2,
-//			BinaryPredicate pred,
-//			std::random_access_iterator_tag*
-//			)
-//		{
-//			return first1 == last1 ? last1
-//				: sprout::detail::find_end_impl_ra(
-//					first1, last1, first2, last2, pred,
-//					sprout::distance(first1, last1) / 2, last1, last1,
-//					first1
-//					)
-//				;
-//		}
+		template<typename RandomAccessIterator1>
+		inline SPROUT_CONSTEXPR RandomAccessIterator1
+		find_end_impl_check_ra(RandomAccessIterator1 first1, RandomAccessIterator1 last1_, RandomAccessIterator1 searched) {
+			return searched == first1 ? searched
+				: last1_
+				;
+		}
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR RandomAccessIterator1
+		find_end_impl_ra(
+			RandomAccessIterator1 first1, RandomAccessIterator1 last1,
+			RandomAccessIterator2 first2, RandomAccessIterator2 last2,
+			BinaryPredicate pred,
+			typename std::iterator_traits<RandomAccessIterator1>::difference_type pivot, RandomAccessIterator1 last1_,
+			RandomAccessIterator1 searched
+			)
+		{
+			return searched != last1_ ? searched
+				: pivot == 0
+				? sprout::detail::find_end_impl_check_ra(
+					first1, last1_,
+					sprout::detail::search_one(first1, last1_, first2, last2, pred)
+					)
+				: sprout::detail::find_end_impl_ra(
+					first1, sprout::next(first1, pivot), first2, last2, pred,
+					pivot / 2, last1_,
+					sprout::detail::find_end_impl_ra(
+						sprout::next(first1, pivot), last1, first2, last2, pred,
+						(sprout::distance(first1, last1) - pivot) / 2, last1_,
+						last1_
+						)
+					)
+				;
+		}
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR RandomAccessIterator1
+		find_end_impl_ra1(
+			RandomAccessIterator1 first1, RandomAccessIterator1 last1,
+			RandomAccessIterator2 first2, RandomAccessIterator2 last2,
+			BinaryPredicate pred,
+			typename std::iterator_traits<RandomAccessIterator1>::difference_type len1,
+			typename std::iterator_traits<RandomAccessIterator2>::difference_type len2
+			)
+		{
+			return len1 < len2 ? last1
+				: sprout::detail::find_end_impl_ra(
+					first1, last1 - len2 + 1, first2, last2, pred,
+					(len1 - len2 + 1) / 2, last1, last1
+					)
+				;
+		}
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR typename std::enable_if<
+			sprout::is_constant_distance_iterator<RandomAccessIterator1>::value
+			&& sprout::is_constant_distance_iterator<RandomAccessIterator2>::value,
+			RandomAccessIterator1
+		>::type
+		find_end(
+			RandomAccessIterator1 first1, RandomAccessIterator1 last1,
+			RandomAccessIterator2 first2, RandomAccessIterator2 last2,
+			BinaryPredicate pred,
+			std::random_access_iterator_tag*
+			)
+		{
+			return sprout::detail::find_end_impl_ra1(
+					first1, last1, first2, last2, pred,
+					sprout::distance(first1, last1), sprout::distance(first2, last2)
+					)
+				;
+		}
+
+		template<typename BidirectionalIterator1>
+		inline SPROUT_CONSTEXPR sprout::pair<BidirectionalIterator1, BidirectionalIterator1>
+		find_end_impl_check_bi(
+			sprout::pair<BidirectionalIterator1, BidirectionalIterator1> const& current,
+			BidirectionalIterator1 first1, sprout::pair<BidirectionalIterator1, bool> searched
+			)
+		{
+			typedef sprout::pair<BidirectionalIterator1, BidirectionalIterator1> type;
+			return searched.second ? type(first1, current.second)
+				: searched.first == current.first ? type(sprout::prev(current.first), current.second)
+				: type(current.first, searched.first)
+				;
+		}
+		template<typename BidirectionalIterator1, typename BidirectionalIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR sprout::pair<BidirectionalIterator1, BidirectionalIterator1>
+		find_end_impl_bi1(
+			sprout::pair<BidirectionalIterator1, BidirectionalIterator1> const& current,
+			BidirectionalIterator1 first1, BidirectionalIterator1 last1,
+			BidirectionalIterator2 first2, BidirectionalIterator2 last2, BinaryPredicate pred,
+			typename std::iterator_traits<BidirectionalIterator1>::difference_type n
+			)
+		{
+			return current.second != last1 || current.first == first1 ? current
+				: n == 1 ? sprout::detail::find_end_impl_check_bi(
+					current, first1,
+					sprout::detail::search_one_rev(first1, current.first, first2, last2, pred)
+					)
+				: sprout::detail::find_end_impl_bi1(
+					sprout::detail::find_end_impl_bi1(
+						current,
+						first1, last1, first2, last2, pred, n / 2
+						),
+					first1, last1, first2, last2, pred, n - n / 2
+					)
+				;
+		}
+		template<typename BidirectionalIterator1, typename BidirectionalIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR sprout::pair<BidirectionalIterator1, BidirectionalIterator1>
+		find_end_impl_bi(
+			sprout::pair<BidirectionalIterator1, BidirectionalIterator1> const& current,
+			BidirectionalIterator1 first1, BidirectionalIterator1 last1,
+			BidirectionalIterator2 first2, BidirectionalIterator2 last2, BinaryPredicate pred,
+			typename std::iterator_traits<BidirectionalIterator1>::difference_type n
+			)
+		{
+			return current.second != last1 || current.first == first1 ? current
+				: sprout::detail::find_end_impl_bi(
+					sprout::detail::find_end_impl_bi1(
+						current,
+						first1, last1, first2, last2, pred, n
+						),
+					first1, last1, first2, last2, pred, n * 2
+					)
+				;
+		}
+		template<typename BidirectionalIterator1, typename BidirectionalIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR BidirectionalIterator1
+		find_end(
+			BidirectionalIterator1 first1, BidirectionalIterator1 last1,
+			BidirectionalIterator2 first2, BidirectionalIterator2 last2,
+			BinaryPredicate pred,
+			std::bidirectional_iterator_tag*
+			)
+		{
+			typedef sprout::pair<BidirectionalIterator1, BidirectionalIterator1> type;
+			return sprout::detail::find_end_impl_bi(type(last1, last1), first1, last1, first2, last2, pred, 1).second;
+		}
 
 		template<typename ForwardIterator1>
 		inline SPROUT_CONSTEXPR sprout::pair<ForwardIterator1, ForwardIterator1>
@@ -161,8 +235,8 @@ namespace sprout {
 		BinaryPredicate pred
 		)
 	{
-		typedef typename std::iterator_traits<ForwardIterator1>::iterator_category* category;
-		return sprout::detail::find_end(first1, last1, first2, last2, pred, category());
+		typedef typename sprout::common_iterator_category<ForwardIterator1, ForwardIterator2>::type* category;
+		return first1 == last1 || first2 == last2 ? last1 : sprout::detail::find_end(first1, last1, first2, last2, pred, category());
 	}
 
 	template<typename ForwardIterator1, typename ForwardIterator2>
diff --git a/sprout/detail/algorithm/search_one_rev.hpp b/sprout/detail/algorithm/search_one_rev.hpp
new file mode 100644
index 00000000..93cd1d85
--- /dev/null
+++ b/sprout/detail/algorithm/search_one_rev.hpp
@@ -0,0 +1,109 @@
+/*=============================================================================
+  Copyright (c) 2011-2013 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_DETAIL_ALGORITHM_SEARCH_ONE_REV_HPP
+#define SPROUT_DETAIL_ALGORITHM_SEARCH_ONE_REV_HPP
+
+#include <iterator>
+#include <sprout/config.hpp>
+#include <sprout/iterator/operation.hpp>
+#include <sprout/functional/equal_to.hpp>
+#include <sprout/tuple/tuple/tuple.hpp>
+#include <sprout/tuple/tuple/get.hpp>
+#include <sprout/utility/pair/pair.hpp>
+
+namespace sprout {
+	namespace detail {
+		template<typename BidirectionalIterator1, typename BidirectionalIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR sprout::tuples::tuple<BidirectionalIterator1, BidirectionalIterator2, bool>
+		search_one_rev_impl_1(
+			sprout::tuples::tuple<BidirectionalIterator1, BidirectionalIterator2, bool> const& current,
+			BidirectionalIterator1 first1, BidirectionalIterator2 first2, BinaryPredicate pred,
+			typename std::iterator_traits<BidirectionalIterator1>::difference_type n
+			)
+		{
+			typedef sprout::tuples::tuple<BidirectionalIterator1, BidirectionalIterator2, bool> type;
+			return sprout::tuples::get<2>(current) ? current
+				: sprout::tuples::get<1>(current) == first2 ? type(sprout::tuples::get<0>(current), first2, true)
+				: sprout::tuples::get<0>(current) == first1 ? type(first1, sprout::tuples::get<1>(current), true)
+				: n == 1 ? pred(*sprout::prev(sprout::tuples::get<0>(current)), *sprout::prev(sprout::tuples::get<1>(current)))
+						? type(sprout::prev(sprout::tuples::get<0>(current)), sprout::prev(sprout::tuples::get<1>(current)), false)
+						: type(sprout::tuples::get<0>(current), sprout::tuples::get<1>(current), true)
+				: sprout::detail::search_one_rev_impl_1(
+					sprout::detail::search_one_rev_impl_1(
+						current,
+						first1, first2, pred, n / 2
+						),
+					first1, first2, pred, n - n / 2
+					)
+				;
+		}
+		template<typename BidirectionalIterator1, typename BidirectionalIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR sprout::tuples::tuple<BidirectionalIterator1, BidirectionalIterator2, bool>
+		search_one_rev_impl(
+			sprout::tuples::tuple<BidirectionalIterator1, BidirectionalIterator2, bool> const& current,
+			BidirectionalIterator1 first1, BidirectionalIterator2 first2, BinaryPredicate pred,
+			typename std::iterator_traits<BidirectionalIterator1>::difference_type n
+			)
+		{
+			typedef sprout::tuples::tuple<BidirectionalIterator1, BidirectionalIterator2, bool> type;
+			return sprout::tuples::get<2>(current) ? current
+				: sprout::tuples::get<1>(current) == first2 ? type(sprout::tuples::get<0>(current), first2, true)
+				: sprout::tuples::get<0>(current) == first1 ? type(first1, sprout::tuples::get<1>(current), true)
+				: sprout::detail::search_one_rev_impl(
+					sprout::detail::search_one_rev_impl_1(
+						current,
+						first1, first2, pred, n
+						),
+					first1, first2, pred, n * 2
+					)
+				;
+		}
+		template<typename BidirectionalIterator1, typename BidirectionalIterator2>
+		inline SPROUT_CONSTEXPR sprout::pair<BidirectionalIterator1, bool>
+		search_one_rev_check(
+			sprout::tuples::tuple<BidirectionalIterator1, BidirectionalIterator2, bool> const& result,
+			BidirectionalIterator1 first1, BidirectionalIterator1 last1, BidirectionalIterator2 first2
+			)
+		{
+			typedef sprout::pair<BidirectionalIterator1, bool> type;
+			return sprout::tuples::get<1>(result) == first2 ? type(sprout::tuples::get<0>(result), false)
+				: type(last1, sprout::tuples::get<0>(result) == first1)
+				;
+		}
+
+		//
+		// search_one_rev
+		//
+		//	recursion depth:
+		//		O(log(N1+N2))
+		//
+		template<typename BidirectionalIterator1, typename BidirectionalIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR sprout::pair<BidirectionalIterator1, bool>
+		search_one_rev(
+			BidirectionalIterator1 first1, BidirectionalIterator1 last1,
+			BidirectionalIterator2 first2, BidirectionalIterator2 last2, BinaryPredicate pred
+			)
+		{
+			typedef sprout::tuples::tuple<BidirectionalIterator1, BidirectionalIterator2, bool> type;
+			return sprout::detail::search_one_rev_check(
+				sprout::detail::search_one_rev_impl(type(last1, last2, false), first1, first2, pred, 1),
+				first1, last1, first2);
+		}
+		template<typename BidirectionalIterator1, typename BidirectionalIterator2>
+		inline SPROUT_CONSTEXPR sprout::pair<BidirectionalIterator1, bool>
+		search_one_rev(
+			BidirectionalIterator1 first1, BidirectionalIterator1 last1,
+			BidirectionalIterator2 first2, BidirectionalIterator2 last2
+			)
+		{
+			return sprout::detail::search_one(first1, last1, first2, last2, sprout::equal_to<>());
+		}
+	}	// namespace detail
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_DETAIL_ALGORITHM_SEARCH_ONE_REV_HPP