libboost-container1.71-dev 1.71.0-6ubuntu1 (amd64 binary) in ubuntu focal

 This package forms part of the Boost C++ Libraries collection.
 .
 Boost.Container library implements several well-known containers,
 including STL containers. The aim of the library is to offers
 advanced features not present in standard containers or to offer the
 latest standard draft features for compilers that don't comply with
 the latest C++ standard.
 .
 In short, what does Boost.Container offer?
 .
  * Move semantics are implemented, including move emulation
    for pre-C++11 compilers.
  * New advanced features (e.g. placement insertion,
    recursive containers) are present.
  * Containers support stateful allocators and are compatible with
    Boost.Interprocess (they can be safely placed in shared memory).
  * The library offers new useful containers:
    * flat_map, flat_set, flat_multimap and flat_multiset: drop-in
      replacements for standard associative containers but more
      memory friendly and with faster searches.
    * stable_vector: a std::list and std::vector hybrid container:
      vector-like random-access iterators and list-like iterator
      stability in insertions and erasures.
    * slist: the classic pre-standard singly linked list implementation
      offering constant-time size(). Note that C++11 forward_list has no size().