Complexity: k + m, where k is the number of elements in r and m is the length of stuff.
DList.insertBefore
size_t insertBefore(Stuff)(Range r, Stuff stuff)Inserts stuff after range r, which must be a non-empty range previously extracted from this container.
stuff can be a value convertible to T or a range of objects convertible to T. The stable version behaves the same, but guarantees that ranges iterating over the container are never invalidated.
Returns
The number of values inserted.