What algorithm is used for accessing an element by index in a linked list and what is its time complexity?

In a linked list (LinkedList), accessing an element by index involves sequential traversal from the beginning of the list to the desired element. The algorithm:

1. Start from the head of the list.
2. Move through the links to the next element, increasing the counter.
3. When the counter reaches the desired index, return the current element.

The time complexity of such access is O(n), where n is the index of the element, since it requires traversing n elements.

Unlike an array, where access by index is O(1), in a linked list, direct access is not possible without sequential traversal.