equal_range

Interface

template<typename ForwardIterator, typename T>
inline SPROUT_CONSTEXPR sprout::pair<ForwardIterator, ForwardIterator>
equal_range(ForwardIterator first, ForwardIterator last, T const& value);

template<typename ForwardIterator, typename T, typename Compare>
inline SPROUT_CONSTEXPR sprout::pair<ForwardIterator, ForwardIterator>
equal_range(ForwardIterator first, ForwardIterator last, T const& value, Compare comp);

Requires

The elements e of [first,last) shall be partitioned with respect to the expressions e < value and !(value < e) or comp(e, value) and !comp(value, e).

Also, for all elements e of [first, last), e < value shall imply !(value < e) or comp(e, value) shall imply !comp(value, e).

Returns

make_pair(lower_bound(first, last, value), upper_bound(first, last, value))

or

make_pair(lower_bound(first, last, value, comp), upper_bound(first, last, value, comp))

Examples

#include <sprout/algorithm/equal_range.hpp>
#include <sprout/algorithm/all_of_equal.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::equal_range(begin(input), end(input), 5);
static_assert(result.first - begin(input) == 3, "a lower bound position is 3.");
static_assert(result.second - begin(input) == 7, "a upper bound position is 7.");
static_assert(sprout::all_of_equal(result.first, result.second. 5), "all of result range is equal to 5.");

Complexity

At most 2 * log2(last - first) + O(1) comparisons.

Recursive function invocations in O(logN) (logarithmic) depth.

Header

sprout/algorithm/equal_range.hpp

Convenience header: sprout/algorithm.hpp