boost::container::erase_if
// In header: <boost/container/flat_set.hpp> template<typename K, typename C, typename A, typename Pred> flat_set< K, C, A >::size_type erase_if(flat_set< K, C, A > & c, Pred pred);
Effects: Erases all elements that satisfy the predicate pred from the container c.
Complexity: Linear.