diff --git a/libs/algorithm/test/count.cpp b/libs/algorithm/test/count.cpp
new file mode 100644
index 00000000..7db9b1a3
--- /dev/null
+++ b/libs/algorithm/test/count.cpp
@@ -0,0 +1,56 @@
+#ifndef SPROUT_LIBS_ALGORITHM_TEST_COUNT_CPP
+#define SPROUT_LIBS_ALGORITHM_TEST_COUNT_CPP
+
+#include <sprout/algorithm/count.hpp>
+#include <sprout/array.hpp>
+#include <sprout/container.hpp>
+#include <testspr/tools.hpp>
+
+namespace testspr {
+	static void algorithm_count_test() {
+		using namespace sprout;
+		{
+			SPROUT_STATIC_CONSTEXPR auto arr1 = array<int, 10>{{1, 2, 3, 5, 5, 5, 5, 8, 9, 10}};
+
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::count(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					5
+					);
+				TESTSPR_BOTH_ASSERT(result == 4);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::count(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					11
+					);
+				TESTSPR_BOTH_ASSERT(result == 0);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::count(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					5
+					);
+				TESTSPR_BOTH_ASSERT(result == 2);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::count(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					11
+					);
+				TESTSPR_BOTH_ASSERT(result == 0);
+			}
+		}
+	}
+}	// namespace testspr
+
+#ifndef TESTSPR_CPP_INCLUDE
+#	define TESTSPR_TEST_FUNCTION testspr::algorithm_count_test
+#	include <testspr/include_main.hpp>
+#endif
+
+#endif	// #ifndef SPROUT_LIBS_ALGORITHM_TEST_COUNT_CPP
diff --git a/libs/algorithm/test/count_if.cpp b/libs/algorithm/test/count_if.cpp
new file mode 100644
index 00000000..ac61bfbf
--- /dev/null
+++ b/libs/algorithm/test/count_if.cpp
@@ -0,0 +1,56 @@
+#ifndef SPROUT_LIBS_ALGORITHM_TEST_COUNT_IF_CPP
+#define SPROUT_LIBS_ALGORITHM_TEST_COUNT_IF_CPP
+
+#include <sprout/algorithm/count_if.hpp>
+#include <sprout/array.hpp>
+#include <sprout/container.hpp>
+#include <testspr/tools.hpp>
+
+namespace testspr {
+	static void algorithm_count_if_test() {
+		using namespace sprout;
+		{
+			SPROUT_STATIC_CONSTEXPR auto arr1 = array<int, 10>{{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};
+
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::count_if(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					testspr::is_odd<int>()
+					);
+				TESTSPR_BOTH_ASSERT(result == 5);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::count_if(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					testspr::less_than<int>(8)
+					);
+				TESTSPR_BOTH_ASSERT(result == 7);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::count_if(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					testspr::is_odd<int>()
+					);
+				TESTSPR_BOTH_ASSERT(result == 3);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::count_if(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					testspr::less_than<int>(8)
+					);
+				TESTSPR_BOTH_ASSERT(result == 5);
+			}
+		}
+	}
+}	// namespace testspr
+
+#ifndef TESTSPR_CPP_INCLUDE
+#	define TESTSPR_TEST_FUNCTION testspr::algorithm_count_if_test
+#	include <testspr/include_main.hpp>
+#endif
+
+#endif	// #ifndef SPROUT_LIBS_ALGORITHM_TEST_COUNT_IF_CPP
diff --git a/libs/algorithm/test/equal.cpp b/libs/algorithm/test/equal.cpp
new file mode 100644
index 00000000..40f3a7c6
--- /dev/null
+++ b/libs/algorithm/test/equal.cpp
@@ -0,0 +1,95 @@
+#ifndef SPROUT_LIBS_ALGORITHM_TEST_EQUAL_CPP
+#define SPROUT_LIBS_ALGORITHM_TEST_EQUAL_CPP
+
+#include <sprout/algorithm/equal.hpp>
+#include <sprout/array.hpp>
+#include <sprout/container.hpp>
+#include <testspr/tools.hpp>
+
+namespace testspr {
+	static void algorithm_equal_test() {
+		using namespace sprout;
+		{
+			SPROUT_STATIC_CONSTEXPR auto arr1 = array<int, 10>{{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};
+			SPROUT_STATIC_CONSTEXPR auto arr2 = array<int, 10>{{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};
+			SPROUT_STATIC_CONSTEXPR auto arr3 = array<int, 10>{{1, 2, 3, 4, 5, 6, 7, 10, 9, 8}};
+
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::equal(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr2)
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::equal(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr3)
+					);
+				TESTSPR_BOTH_ASSERT(!result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::equal(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr2)
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::equal(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr3)
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::equal(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr2),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::equal(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr3),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(!result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::equal(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr2),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::equal(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr3),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+		}
+	}
+}	// namespace testspr
+
+#ifndef TESTSPR_CPP_INCLUDE
+#	define TESTSPR_TEST_FUNCTION testspr::algorithm_equal_test
+#	include <testspr/include_main.hpp>
+#endif
+
+#endif	// #ifndef SPROUT_LIBS_ALGORITHM_TEST_EQUAL_CPP
diff --git a/libs/algorithm/test/is_permutation.cpp b/libs/algorithm/test/is_permutation.cpp
new file mode 100644
index 00000000..02c57d25
--- /dev/null
+++ b/libs/algorithm/test/is_permutation.cpp
@@ -0,0 +1,95 @@
+#ifndef SPROUT_LIBS_ALGORITHM_TEST_IS_PERMUTATION_CPP
+#define SPROUT_LIBS_ALGORITHM_TEST_IS_PERMUTATION_CPP
+
+#include <sprout/algorithm/is_permutation.hpp>
+#include <sprout/array.hpp>
+#include <sprout/container.hpp>
+#include <testspr/tools.hpp>
+
+namespace testspr {
+	static void algorithm_is_permutation_test() {
+		using namespace sprout;
+		{
+			SPROUT_STATIC_CONSTEXPR auto arr1 = array<int, 10>{{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};
+			SPROUT_STATIC_CONSTEXPR auto arr2 = array<int, 10>{{10, 9, 8, 1, 2, 3, 4, 5, 6, 7}};
+			SPROUT_STATIC_CONSTEXPR auto arr3 = array<int, 10>{{5, 4, 3, 2, 1, 11, 10, 9, 8, 7}};
+
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::is_permutation(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr2)
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::is_permutation(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr3)
+					);
+				TESTSPR_BOTH_ASSERT(!result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::is_permutation(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr2)
+					);
+				TESTSPR_BOTH_ASSERT(!result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::is_permutation(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr3)
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::is_permutation(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr2),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::is_permutation(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr3),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(!result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::is_permutation(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr2),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(!result);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto result = sprout::is_permutation(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr3),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(result);
+			}
+		}
+	}
+}	// namespace testspr
+
+#ifndef TESTSPR_CPP_INCLUDE
+#	define TESTSPR_TEST_FUNCTION testspr::algorithm_is_permutation_test
+#	include <testspr/include_main.hpp>
+#endif
+
+#endif	// #ifndef SPROUT_LIBS_ALGORITHM_TEST_IS_PERMUTATION_CPP
diff --git a/libs/algorithm/test/mismatch.cpp b/libs/algorithm/test/mismatch.cpp
new file mode 100644
index 00000000..07fef740
--- /dev/null
+++ b/libs/algorithm/test/mismatch.cpp
@@ -0,0 +1,95 @@
+#ifndef SPROUT_LIBS_ALGORITHM_TEST_MISMATCH_CPP
+#define SPROUT_LIBS_ALGORITHM_TEST_MISMATCH_CPP
+
+#include <sprout/algorithm/mismatch.hpp>
+#include <sprout/array.hpp>
+#include <sprout/container.hpp>
+#include <testspr/tools.hpp>
+
+namespace testspr {
+	static void algorithm_mismatch_test() {
+		using namespace sprout;
+		{
+			SPROUT_STATIC_CONSTEXPR auto arr1 = array<int, 10>{{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};
+			SPROUT_STATIC_CONSTEXPR auto arr2 = array<int, 10>{{1, 2, 3, 4, 5, 6, 7, 10, 9, 8}};
+			SPROUT_STATIC_CONSTEXPR auto arr3 = array<int, 10>{{10, 9, 8, 1, 2, 3, 4, 5, 6, 7}};
+
+			{
+				SPROUT_STATIC_CONSTEXPR auto found = sprout::mismatch(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr2)
+					);
+				TESTSPR_BOTH_ASSERT(found.first == sprout::begin(arr1) + 7);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto found = sprout::mismatch(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr3)
+					);
+				TESTSPR_BOTH_ASSERT(found.first == sprout::begin(arr1));
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto found = sprout::mismatch(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr2)
+					);
+				TESTSPR_BOTH_ASSERT(found.first == sprout::begin(arr1) + 5);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto found = sprout::mismatch(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr3)
+					);
+				TESTSPR_BOTH_ASSERT(found.first == sprout::begin(arr1));
+			}
+
+			{
+				SPROUT_STATIC_CONSTEXPR auto found = sprout::mismatch(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr2),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(found.first == sprout::begin(arr1) + 7);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto found = sprout::mismatch(
+					sprout::begin(arr1),
+					sprout::end(arr1),
+					sprout::begin(arr3),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(found.first == sprout::begin(arr1));
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto found = sprout::mismatch(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr2),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(found.first == sprout::begin(arr1) + 5);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto found = sprout::mismatch(
+					sprout::begin(arr1),
+					sprout::begin(arr1) + 5,
+					sprout::begin(arr3),
+					testspr::equal_to<int>()
+					);
+				TESTSPR_BOTH_ASSERT(found.first == sprout::begin(arr1));
+			}
+		}
+	}
+}	// namespace testspr
+
+#ifndef TESTSPR_CPP_INCLUDE
+#	define TESTSPR_TEST_FUNCTION testspr::algorithm_mismatch_test
+#	include <testspr/include_main.hpp>
+#endif
+
+#endif	// #ifndef SPROUT_LIBS_ALGORITHM_TEST_MISMATCH_CPP
diff --git a/libs/algorithm/test/non_modifying.cpp b/libs/algorithm/test/non_modifying.cpp
index 3d68cf03..51435d14 100644
--- a/libs/algorithm/test/non_modifying.cpp
+++ b/libs/algorithm/test/non_modifying.cpp
@@ -16,6 +16,11 @@
 #include "./find_end.cpp"
 #include "./find_first_of.cpp"
 #include "./adjacent_find.cpp"
+#include "./count.cpp"
+#include "./count_if.cpp"
+#include "./mismatch.cpp"
+#include "./equal.cpp"
+#include "./is_permutation.cpp"
 
 #ifdef TESTSPR_CPP_INCLUDE_DISABLE_SPROUT_LIBS_ALGORITHM_TEST_NON_MODIFYIING_CPP
 #	undef TESTSPR_CPP_INCLUDE
@@ -33,6 +38,11 @@ namespace testspr {
 		testspr::algorithm_find_end_test();
 		testspr::algorithm_find_first_of_test();
 		testspr::algorithm_adjacent_find_test();
+		testspr::algorithm_count_test();
+		testspr::algorithm_count_if_test();
+		testspr::algorithm_mismatch_test();
+		testspr::algorithm_equal_test();
+		testspr::algorithm_is_permutation_test();
 	}
 }	// namespace testspr
 
diff --git a/sprout/algorithm/count.hpp b/sprout/algorithm/count.hpp
index c5cacdef..2a2ba6e2 100644
--- a/sprout/algorithm/count.hpp
+++ b/sprout/algorithm/count.hpp
@@ -4,17 +4,65 @@
 #include <iterator>
 #include <sprout/config.hpp>
 #include <sprout/iterator/operation.hpp>
+#include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
 
 namespace sprout {
-	// Copyright (C) 2011 RiSK (sscrisk)
+	namespace detail {
+		template<typename RandomAccessIterator, typename T>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<RandomAccessIterator>::difference_type
+		count_impl_ra(
+			RandomAccessIterator first, RandomAccessIterator last, T const& value,
+			typename std::iterator_traits<RandomAccessIterator>::difference_type pivot
+			)
+		{
+			return pivot == 0 ? (*first == value ? 1 : 0)
+				: sprout::detail::count_impl_ra(
+					first, sprout::next(first, pivot), value,
+					pivot / 2
+					)
+					+ sprout::detail::count_impl_ra(
+						sprout::next(first, pivot), last, value,
+						(NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) - pivot) / 2
+						)
+				;
+		}
+		template<typename RandomAccessIterator, typename T>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<RandomAccessIterator>::difference_type
+		count(
+			RandomAccessIterator first, RandomAccessIterator last, T const& value,
+			std::random_access_iterator_tag*
+			)
+		{
+			return first == last ? 0
+				: sprout::detail::count_impl_ra(first, last, value, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2)
+				;
+		}
+
+		// Copyright (C) 2011 RiSK (sscrisk)
+		template<typename InputIterator, typename T>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
+		count_impl(InputIterator first, InputIterator last, T const& value) {
+			return first == last ? 0
+				: (*first == value ? 1 : 0) + sprout::detail::count_impl(sprout::next(first), last, value)
+				;
+		}
+		template<typename InputIterator, typename T>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
+		count(
+			InputIterator first, InputIterator last, T const& value,
+			void*
+			)
+		{
+			return sprout::detail::count_impl(first, last, value);
+		}
+	}	//namespace detail
 
 	// 25.2.9 Count
 	template<typename InputIterator, typename T>
 	inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
 	count(InputIterator first, InputIterator last, T const& value) {
-		return first == last ? 0
-			: (*first == value ? 1 : 0) + sprout::count(sprout::next(first), last, value)
-			;
+		typedef typename std::iterator_traits<InputIterator>::iterator_category* category;
+		return sprout::detail::count(first, last, value, category());
 	}
 }	// namespace sprout
 
diff --git a/sprout/algorithm/count_if.hpp b/sprout/algorithm/count_if.hpp
index 01aaf721..e49f9b77 100644
--- a/sprout/algorithm/count_if.hpp
+++ b/sprout/algorithm/count_if.hpp
@@ -4,17 +4,65 @@
 #include <iterator>
 #include <sprout/config.hpp>
 #include <sprout/iterator/operation.hpp>
+#include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
 
 namespace sprout {
-	// Copyright (C) 2011 RiSK (sscrisk)
+	namespace detail {
+		template<typename RandomAccessIterator, typename Predicate>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<RandomAccessIterator>::difference_type
+		count_if_impl_ra(
+			RandomAccessIterator first, RandomAccessIterator last, Predicate pred,
+			typename std::iterator_traits<RandomAccessIterator>::difference_type pivot
+			)
+		{
+			return pivot == 0 ? (pred(*first) ? 1 : 0)
+				: sprout::detail::count_if_impl_ra(
+					first, sprout::next(first, pivot), pred,
+					pivot / 2
+					)
+					+ sprout::detail::count_if_impl_ra(
+						sprout::next(first, pivot), last, pred,
+						(NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) - pivot) / 2
+						)
+				;
+		}
+		template<typename RandomAccessIterator, typename Predicate>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<RandomAccessIterator>::difference_type
+		count_if(
+			RandomAccessIterator first, RandomAccessIterator last, Predicate pred,
+			std::random_access_iterator_tag*
+			)
+		{
+			return first == last ? 0
+				: sprout::detail::count_if_impl_ra(first, last, pred, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2)
+				;
+		}
+
+		// Copyright (C) 2011 RiSK (sscrisk)
+		template<typename InputIterator, typename Predicate>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
+		count_if_impl(InputIterator first, InputIterator last, Predicate pred) {
+			return first == last ? 0
+				: (pred(*first) ? 1 : 0) + sprout::detail::count_if_impl(sprout::next(first), last, pred)
+				;
+		}
+		template<typename InputIterator, typename Predicate>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
+		count_if(
+			InputIterator first, InputIterator last, Predicate pred,
+			void*
+			)
+		{
+			return sprout::detail::count_if_impl(first, last, pred);
+		}
+	}	//namespace detail
 
 	// 25.2.9 Count
 	template<typename InputIterator, typename Predicate>
 	inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
 	count_if(InputIterator first, InputIterator last, Predicate pred) {
-		return first == last ? 0
-			: (pred(*first) ? 1 : 0) + sprout::count_if(sprout::next(first), last, pred)
-			;
+		typedef typename std::iterator_traits<InputIterator>::iterator_category* category;
+		return sprout::detail::count_if(first, last, pred, category());
 	}
 }	// namespace sprout
 
diff --git a/sprout/algorithm/equal.hpp b/sprout/algorithm/equal.hpp
index 2b98ff57..daabd085 100644
--- a/sprout/algorithm/equal.hpp
+++ b/sprout/algorithm/equal.hpp
@@ -1,27 +1,78 @@
 #ifndef SPROUT_ALGORITHM_EQUAL_HPP
 #define SPROUT_ALGORITHM_EQUAL_HPP
 
+#include <iterator>
 #include <sprout/config.hpp>
 #include <sprout/iterator/operation.hpp>
+#include <sprout/functional/equal_to.hpp>
+#include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
 
 namespace sprout {
-	// Copyright (C) 2011 RiSK (sscrisk)
+	namespace detail {
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR bool
+		equal_impl_ra(
+			RandomAccessIterator1 first1, RandomAccessIterator1 last1, RandomAccessIterator2 first2, BinaryPredicate pred,
+			typename std::iterator_traits<RandomAccessIterator1>::difference_type pivot
+			)
+		{
+			return pivot == 0 ? pred(*first1, *first2)
+				: sprout::detail::equal_impl_ra(
+					first1, sprout::next(first1, pivot), first2, pred,
+					pivot / 2
+					)
+					&& sprout::detail::equal_impl_ra(
+						sprout::next(first1, pivot), last1, sprout::next(first2, pivot), pred,
+						(NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1) - pivot) / 2
+						)
+				;
+		}
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR bool
+		equal(
+			RandomAccessIterator1 first1, RandomAccessIterator1 last1, RandomAccessIterator2 first2, BinaryPredicate pred,
+			std::random_access_iterator_tag*
+			)
+		{
+			return first1 == last1 ? true
+				: sprout::detail::equal_impl_ra(
+					first1, last1, first2, pred,
+					NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1) / 2
+					)
+				;
+		}
+
+		// Copyright (C) 2011 RiSK (sscrisk)
+		template<typename InputIterator1, typename InputIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR bool
+		equal_impl(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, BinaryPredicate pred) {
+			return first1 == last1 ? true
+				: pred(*first1, *first2) && sprout::detail::equal_impl(sprout::next(first1), last1, sprout::next(first2), pred)
+				;
+		}
+		template<typename InputIterator1, typename InputIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR bool
+		equal(
+			InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, BinaryPredicate pred,
+			void*
+			)
+		{
+			return sprout::detail::equal_impl(first1, last1, first2, pred);
+		}
+	}	//namespace detail
 
 	// 25.2.11 Equal
-	template<typename InputIterator1, typename InputIterator2>
-	inline SPROUT_CONSTEXPR bool
-	equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2) {
-		return first1 == last1 ? true
-			: *first1 == *first2 && sprout::equal(sprout::next(first1), last1, sprout::next(first2))
-			;
-	}
-
 	template<typename InputIterator1, typename InputIterator2, typename BinaryPredicate>
 	inline SPROUT_CONSTEXPR bool
 	equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, BinaryPredicate pred) {
-		return first1 == last1 ? true
-			: pred(*first1, *first2) && sprout::equal(sprout::next(first1), last1, sprout::next(first2), pred)
-			;
+		typedef typename sprout::common_iterator_category<InputIterator1, InputIterator2>::type* category;
+		return sprout::detail::equal(first1, last1, first2, pred, category());
+	}
+
+	template<typename InputIterator1, typename InputIterator2>
+	inline SPROUT_CONSTEXPR bool
+	equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2) {
+		return sprout::equal(first1, last1, first2, sprout::equal_to<>());
 	}
 }	// namespace sprout
 
diff --git a/sprout/algorithm/find_end.hpp b/sprout/algorithm/find_end.hpp
index 962e9dff..87e03b2c 100644
--- a/sprout/algorithm/find_end.hpp
+++ b/sprout/algorithm/find_end.hpp
@@ -4,25 +4,9 @@
 #include <sprout/config.hpp>
 #include <sprout/iterator/operation.hpp>
 #include <sprout/algorithm/search.hpp>
+#include <sprout/functional/equal_to.hpp>
 
 namespace sprout {
-	namespace detail {
-		// Copyright (C) 2011 RiSK (sscrisk)
-
-		template<typename Iterator1, typename Iterator2>
-		struct iter_equal_to {
-		public:
-			SPROUT_CONSTEXPR bool
-			operator()(
-				typename std::iterator_traits<Iterator1>::value_type const& x,
-				typename std::iterator_traits<Iterator2>::value_type const& y
-				) const
-			{
-				return x == y;
-			}
-		};
-	}	// namespace detail
-
 	namespace detail {
 		template<typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
 		inline SPROUT_CONSTEXPR ForwardIterator1
@@ -81,7 +65,7 @@ namespace sprout {
 		return sprout::find_end(
 			first1, last1,
 			first2, last2,
-			sprout::detail::iter_equal_to<ForwardIterator1, ForwardIterator2>()
+			sprout::equal_to<>()
 			);
 	}
 }	// namespace sprout
diff --git a/sprout/algorithm/find_first_of.hpp b/sprout/algorithm/find_first_of.hpp
index 5ae371ab..2ddd934f 100644
--- a/sprout/algorithm/find_first_of.hpp
+++ b/sprout/algorithm/find_first_of.hpp
@@ -5,8 +5,9 @@
 #include <sprout/config.hpp>
 #include <sprout/iterator/operation.hpp>
 #include <sprout/functional/equal_to.hpp>
+#include <sprout/functional/bind2nd.hpp>
+#include <sprout/algorithm/find_if.hpp>
 #include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
-#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
 
 namespace sprout {
 	namespace detail {
@@ -20,7 +21,7 @@ namespace sprout {
 			)
 		{
 			return found != first1 ? found
-				: pivot == 0 ? sprout::find_if(first2, last2, NS_SSCRISK_CEL_OR_SPROUT::bind2nd(pred, *first1)) != last2 ? first1 : last1
+				: pivot == 0 ? sprout::find_if(first2, last2, sprout::bind2nd(pred, *first1)) != last2 ? first1 : last1
 				: sprout::detail::find_first_of_impl_ra(
 					sprout::next(first1, pivot), last1, first2, last2, pred,
 					(NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1) - pivot) / 2,
@@ -58,7 +59,7 @@ namespace sprout {
 			BinaryPredicate pred
 			)
 		{
-			return first1 == last1 || sprout::find_if(first2, last2, NS_SSCRISK_CEL_OR_SPROUT::bind2nd(pred, *first1)) != last2 ? first1
+			return first1 == last1 || sprout::find_if(first2, last2, sprout::bind2nd(pred, *first1)) != last2 ? first1
 				: sprout::detail::find_first_of_impl(sprout::next(first1), last1, first2, last2, pred)
 				;
 		}
diff --git a/sprout/algorithm/is_permutation.hpp b/sprout/algorithm/is_permutation.hpp
index 37866193..0eba4f5b 100644
--- a/sprout/algorithm/is_permutation.hpp
+++ b/sprout/algorithm/is_permutation.hpp
@@ -1,65 +1,92 @@
 #ifndef SPROUT_ALGORITHM_IS_PERMUTATION_HPP
 #define SPROUT_ALGORITHM_IS_PERMUTATION_HPP
 
+#include <iterator>
 #include <sprout/config.hpp>
 #include <sprout/iterator/operation.hpp>
-#include <sprout/algorithm/count.hpp>
+#include <sprout/functional/equal_to.hpp>
+#include <sprout/functional/bind2nd.hpp>
 #include <sprout/algorithm/count_if.hpp>
 #include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
-#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
 
 namespace sprout {
-	// Copyright (C) 2011 RiSK (sscrisk)
-
 	namespace detail {
-		template<typename ForwardIterator1, typename ForwardIterator2>
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
 		inline SPROUT_CONSTEXPR bool
-		is_permutation_impl(
-			ForwardIterator1 first1, ForwardIterator1 last1,
-			ForwardIterator2 first2, ForwardIterator1 first1_
+		is_permutation_impl_ra(
+			RandomAccessIterator1 first1, RandomAccessIterator1 last1,
+			RandomAccessIterator2 first2, RandomAccessIterator2 last2,
+			BinaryPredicate pred,
+			typename std::iterator_traits<RandomAccessIterator1>::difference_type pivot
 			)
 		{
-			return first1_ == last1 ? true
-				: sprout::count(first1, last1, *first1_)
-					== sprout::count(first2, sprout::next(first2, NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)), *first1_)
-					&& sprout::detail::is_permutation_impl(first1, last1, first2, sprout::next(first1_))
-					? true
-				: false
+			return pivot == 0 ? sprout::count_if(first1, last1, sprout::bind2nd(pred, *first1))
+					<= sprout::count_if(first2, last2, sprout::bind2nd(pred, *first1))
+				: sprout::detail::is_permutation_impl_ra(
+					first1, last1, first2, last2,
+					pred, pivot / 2
+					)
+					&& sprout::detail::is_permutation_impl_ra(
+						sprout::next(first1, pivot), last1, first2, last2,
+						pred, (NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1) - pivot) / 2
+						)
+				;
+		}
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR bool
+		is_permutation(
+			RandomAccessIterator1 first1, RandomAccessIterator1 last1, RandomAccessIterator2 first2, BinaryPredicate pred,
+			std::random_access_iterator_tag*
+			)
+		{
+			return first1 == last1 ? true
+				: sprout::detail::is_permutation_impl_ra(
+					first1, last1, first2, sprout::next(first2, NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)),
+					pred, NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1) / 2
+					)
 				;
 		}
 
+		// Copyright (C) 2011 RiSK (sscrisk)
 		template<typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
 		inline SPROUT_CONSTEXPR bool
 		is_permutation_impl(
 			ForwardIterator1 first1, ForwardIterator1 last1,
-			ForwardIterator2 first2, ForwardIterator1 first1_,
+			ForwardIterator2 first2, ForwardIterator2 last2,
 			BinaryPredicate pred
 			)
 		{
-			return first1_ == last1 ? true
-				: sprout::count_if(first1, last1, NS_SSCRISK_CEL_OR_SPROUT::bind2nd(pred, *first1_))
-					== sprout::count_if(
-						first2, sprout::next(first2, NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)),
-						NS_SSCRISK_CEL_OR_SPROUT::bind2nd(pred, *first1_)
-						)
-					&& sprout::detail::is_permutation_impl(first1, last1, first2, sprout::next(first1_), pred)
-					? true
-				: false
+			return first1 == last1 ? true
+				: sprout::count_if(first1, last1, sprout::bind2nd(pred, *first1))
+					<= sprout::count_if(first2, last2, sprout::bind2nd(pred, *first1))
+					&& sprout::detail::is_permutation_impl(sprout::next(first1), last1, first2, last2, pred)
 				;
 		}
+		template<typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR bool
+		is_permutation(
+			ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2, BinaryPredicate pred,
+			void*
+			)
+		{
+			return sprout::detail::is_permutation_impl(
+				first1, last1, first2, sprout::next(first2, NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)), pred
+				);
+		}
 	}	// namespace detail
 
 	// 25.2.12 Is permutation
-	template<typename ForwardIterator1, typename ForwardIterator2>
-	inline SPROUT_CONSTEXPR bool
-	is_permutation(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2) {
-		return sprout::detail::is_permutation_impl(first1, last1, first2, first1);
-	}
-
 	template<typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
 	inline SPROUT_CONSTEXPR bool
 	is_permutation(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2, BinaryPredicate pred) {
-		return sprout::detail::is_permutation_impl(first1, last1, first2, first1, pred);
+		typedef typename sprout::common_iterator_category<ForwardIterator1, ForwardIterator2>::type* category;
+		return sprout::detail::is_permutation(first1, last1, first2, pred, category());
+	}
+
+	template<typename ForwardIterator1, typename ForwardIterator2>
+	inline SPROUT_CONSTEXPR bool
+	is_permutation(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2) {
+		return sprout::is_permutation(first1, last1, first2, sprout::equal_to<>());
 	}
 }	// namespace sprout
 
diff --git a/sprout/algorithm/mismatch.hpp b/sprout/algorithm/mismatch.hpp
index 888cbf4e..8ba6c148 100644
--- a/sprout/algorithm/mismatch.hpp
+++ b/sprout/algorithm/mismatch.hpp
@@ -1,30 +1,92 @@
 #ifndef SPROUT_ALGORITHM_MISMATCH_HPP
 #define SPROUT_ALGORITHM_MISMATCH_HPP
 
+#include <iterator>
 #include <sprout/config.hpp>
-#include <sprout/iterator/operation.hpp>
 #include <sprout/utility/pair.hpp>
+#include <sprout/iterator/operation.hpp>
+#include <sprout/iterator/type_traits/common.hpp>
+#include <sprout/functional/equal_to.hpp>
+#include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
 
 namespace sprout {
-	// Copyright (C) 2011 RiSK (sscrisk)
+	namespace detail {
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2>
+		inline SPROUT_CONSTEXPR sprout::pair<RandomAccessIterator1, RandomAccessIterator2>
+		mismatch_impl_ra_1(RandomAccessIterator1 first1, RandomAccessIterator2 first2, RandomAccessIterator1 found) {
+			return sprout::pair<RandomAccessIterator1, RandomAccessIterator2>{
+				found, sprout::next(first2, NS_SSCRISK_CEL_OR_SPROUT::distance(first1, found))
+				};
+		}
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR RandomAccessIterator1
+		mismatch_impl_ra(
+			RandomAccessIterator1 first1, RandomAccessIterator1 last1, RandomAccessIterator2 first2, BinaryPredicate pred,
+			typename std::iterator_traits<RandomAccessIterator1>::difference_type pivot, RandomAccessIterator1 found
+			)
+		{
+			return found != first1 ? found
+				: pivot == 0 ? (!pred(*first1, *first2) ? first1 : last1)
+				: sprout::detail::mismatch_impl_ra(
+					sprout::next(first1, pivot), last1, sprout::next(first2, pivot), pred,
+					(NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1) - pivot) / 2,
+					sprout::detail::mismatch_impl_ra(
+						first1, sprout::next(first1, pivot), first2, pred,
+						pivot / 2,
+						first1
+						)
+					)
+				;
+		}
+		template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR sprout::pair<RandomAccessIterator1, RandomAccessIterator2>
+		mismatch(
+			RandomAccessIterator1 first1, RandomAccessIterator1 last1, RandomAccessIterator2 first2, BinaryPredicate pred,
+			std::random_access_iterator_tag*
+			)
+		{
+			return first1 == last1 ? sprout::pair<RandomAccessIterator1, RandomAccessIterator2>{first1, first2}
+				: sprout::detail::mismatch_impl_ra_1(
+					first1, first2,
+					sprout::detail::mismatch_impl_ra(
+						first1, last1, first2, pred,
+						NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1) / 2, first1
+						)
+					)
+				;
+		}
+
+		// Copyright (C) 2011 RiSK (sscrisk)
+		template<typename InputIterator1, typename InputIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR sprout::pair<InputIterator1, InputIterator2>
+		mismatch_impl(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, BinaryPredicate pred) {
+			return first1 == last1 || !pred(*first1, *first2)
+				? sprout::pair<InputIterator1, InputIterator2>{first1, first2}
+				: sprout::detail::mismatch_impl(sprout::next(first1), last1, sprout::next(first2))
+				;
+		}
+		template<typename InputIterator1, typename InputIterator2, typename BinaryPredicate>
+		inline SPROUT_CONSTEXPR sprout::pair<InputIterator1, InputIterator2>
+		mismatch(
+			InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, BinaryPredicate pred,
+			void*
+			)
+		{
+			return sprout::detail::mismatch_impl(first1, last1, first2, pred);
+		}
+	}	//namespace detail
 
 	// 25.2.10 Mismatch
-	template<typename InputIterator1, typename InputIterator2>
-	inline SPROUT_CONSTEXPR sprout::pair<InputIterator1, InputIterator2>
-	mismatch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2) {
-		return first1 == last1 || !(*first1 == *first2)
-			? sprout::pair<InputIterator1, InputIterator2>{first1, first2}
-			: sprout::mismatch(sprout::next(first1), last1, sprout::next(first2))
-			;
-	}
-
 	template<typename InputIterator1, typename InputIterator2, typename BinaryPredicate>
 	inline SPROUT_CONSTEXPR sprout::pair<InputIterator1, InputIterator2>
 	mismatch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, BinaryPredicate pred) {
-		return first1 == last1 || !pred(*first1, *first2)
-			? sprout::pair<InputIterator1, InputIterator2>{first1, first2}
-			: sprout::mismatch(sprout::next(first1), last1, sprout::next(first2))
-			;
+		typedef typename sprout::common_iterator_category<InputIterator1, InputIterator2>::type* category;
+		return sprout::detail::mismatch(first1, last1, first2, pred, category());
+	}
+	template<typename InputIterator1, typename InputIterator2>
+	inline SPROUT_CONSTEXPR sprout::pair<InputIterator1, InputIterator2>
+	mismatch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2) {
+		return sprout::mismatch(first1, last1, first2, sprout::equal_to<>());
 	}
 }	// namespace sprout
 
diff --git a/sprout/detail/pow.hpp b/sprout/detail/pow.hpp
index 020209cd..41a90e8d 100644
--- a/sprout/detail/pow.hpp
+++ b/sprout/detail/pow.hpp
@@ -1,5 +1,6 @@
 #ifndef SPROUT_DETAIL_POW_HPP
 #define SPROUT_DETAIL_POW_HPP
+
 #include <sprout/config.hpp>
 
 namespace sprout {