Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Header <boost/algorithm/cxx14/is_permutation.hpp>

Is a sequence a permutation of another sequence (four iterator versions)

Marshall Clow

namespace boost {
  namespace algorithm {
    template<typename ForwardIterator1, typename ForwardIterator2> 
      bool is_permutation(ForwardIterator1, ForwardIterator1, 
                          ForwardIterator2, ForwardIterator2);
    template<typename ForwardIterator1, typename ForwardIterator2, 
             typename BinaryPredicate> 
      bool is_permutation(ForwardIterator1, ForwardIterator1, 
                          ForwardIterator2, ForwardIterator2, 
                          BinaryPredicate);
  }
}