### - m -

- mapped_type : std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc > , std::unordered_multimap< _Key, _Tp, _Hash, _Pred, _Alloc >
- metadata_const_reference : __gnu_pbds::detail::bin_search_tree_const_node_it_< Node, Const_Iterator, Iterator, _Alloc > , __gnu_pbds::detail::pat_trie_base::_Node_citer< Node, Leaf, Head, Inode, _CIterator, Iterator, _Alloc >
- metadata_reference : __gnu_pbds::lu_counter_policy< Max_Count, _Alloc > , __gnu_pbds::lu_move_to_front_policy< _Alloc >
- metadata_type : __gnu_pbds::detail::bin_search_tree_const_node_it_< Node, Const_Iterator, Iterator, _Alloc > , __gnu_pbds::detail::pat_trie_base::_Node_citer< Node, Leaf, Head, Inode, _CIterator, Iterator, _Alloc > , __gnu_pbds::lu_counter_policy< Max_Count, _Alloc > , __gnu_pbds::lu_move_to_front_policy< _Alloc > , __gnu_pbds::sample_update_policy