[container.requirements.pre]

All of the complexity requirements in this Clause are stated solely in terms of the number of operations on the contained objects.

[Example 1:

The copy constructor of type vector<vector<int> has linear complexity, even though the complexity of copying each contained vector<int> is itself linear.

— end example]

Allocator-aware containers ([container.alloc.reqmts]) other than basic_string construct elements using the function allocator_traits<allocator_type>::rebind_traits<U>::construct and destroy elements using the function allocator_traits<allocator_type>::rebind_traits<U>::destroy ([allocator.traits.members]), where U is either allocator_type::value_type or an internal type used by the container.

These functions are called only for the container's element type, not for internal types used by the container.

[Note 1:

This means, for example, that a node-based container would need to construct nodes containing aligned buffers and call construct to place the element into the buffer.

— end note]