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

This is because the article that you are reading considered "getting to that index" as a separate operation. The article assumes that you are already at the index you wish to perform add(int, E).

To conclude:

Insert or Remove operation = O(1)

Finding node at n^th index = O(n)