Is there a sorted_vector class, which supports insert() etc.?

Question

Often, it is more efficient to use a sorted std::vector instead of a std::set. Does anyone know a library class sorted_vector, which b

Answer 1

Boost.Container flat_set

Boost.Container flat_[multi]map/set containers are ordered-vector based associative containers based on Austern's and Alexandrescu's guidelines. These ordered vector containers have also benefited recently with the addition of move semantics to C++, speeding up insertion and erasure times considerably. Flat associative containers have the following attributes:

• Faster lookup than standard associative containers
• Much faster iteration than standard associative containers.
• Less memory consumption for small objects (and for big objects if shrink_to_fit is used)
• Improved cache performance (data is stored in contiguous memory)
• Non-stable iterators (iterators are invalidated when inserting and erasing elements)
• Non-copyable and non-movable values types can't be stored
• Weaker exception safety than standard associative containers (copy/move constructors can throw when shifting values in erasures and insertions)
• Slower insertion and erasure than standard associative containers (specially for non-movable types)

Live demo:

#include 
#include 
#include 

using namespace std;

int main()
{
    boost::container::flat_set s;
    s.insert(1);
    s.insert(2);
    s.insert(3);
    cout << (s.find(1)!=s.end()) << endl;
    cout << (s.find(4)!=s.end()) << endl;
}

---

jalf: If you want a sorted vector, it is likely better to insert all the elements, and then call std::sort() once, after the insertions.

boost::flat_set can do that automatically:

template 
flat_set(InputIterator first, InputIterator last, 
         const Compare & comp = Compare(), 
         const allocator_type & a = allocator_type());

Effects: Constructs an empty set using the specified comparison object and allocator, and inserts elements from the range [first, last).

Complexity: Linear in N if the range [first, last) is already sorted using comp and otherwise N*log(N), where N is last - first.