fix directory structure

source/libs/algorithm/upper_bound.rst

@@ -0,0 +1,52 @@
+.. _sprout-algorithm-upper_bound:
+###############################################################################
+upper_bound
+###############################################################################
+
+Interface
+========================================
+.. sourcecode:: c++
+
+  template<typename ForwardIterator, typename T>
+  inline SPROUT_CONSTEXPR ForwardIterator
+  upper_bound(ForwardIterator first, ForwardIterator last, T const& value);
+  
+  template<typename ForwardIterator, typename T, typename Compare>
+  inline SPROUT_CONSTEXPR ForwardIterator
+  upper_bound(ForwardIterator first, ForwardIterator last, T const& value, Compare comp);
+
+Requires
+========================================
+
+| The elements e of [first,last) shall be partitioned with respect to the expression ``!(value < e)`` or ``!comp(value, e)``.
+
+Returns
+========================================
+
+| The furthermost iterator i in the range [first,last] such that for any iterator j in the range [first,i) the following corresponding conditions hold: ``!(value < *j)`` or ``!comp(value, *j)``.
+
+Examples
+========================================
+.. sourcecode:: c++
+
+  #include <sprout/algorithm/upper_bound.hpp>
+  #include <sprout/array.hpp>
+  #include <sprout/container.hpp>
+  using namespace sprout;
+
+  SPROUT_STATIC_CONSTEXPR auto input = array<int, 10>{{1, 2, 3, 5, 5, 5, 5, 8, 9, 10}};
+  SPROUT_STATIC_CONSTEXPR auto result = sprout::upper_bound(begin(input), end(input), 5);
+  static_assert(result - begin(input) == 7, "a upper bound position is 7.");
+
+Complexity
+========================================
+
+| At most ``log2(last - first) + O(1)`` comparisons.
+| Recursive function invocations in *O(logN)* (logarithmic) depth.
+
+Header
+========================================
+
+| ``sprout/algorithm/upper_bound.hpp``
+| Convenience header: ``sprout/algorithm.hpp``
+