How is LinkedList's add(int, E) of O(1) complexity?

Question

From the linked-list tag wiki excerpt:

A linked list is a data structure in which the elements contain references to the next (and optionally the pr

Answer 1

The wiki page you quote says:

O(1) insert and removal at any position

Then you ask:

I was surprised to read this – how can the list insert at a random index

Herein lies the confusion: the terms position and index are not being used to mean the same thing. The wiki talks about an iterator or a pointer, not about an index.