Linked list operations that were studied included adding/removing an element at the end or in the middle, and retrieving the kth element.If the iterator is currently pointing to the correct location for insertion or removal, which of the following statements about these doubly-linked list operations is correct?
A)The least expensive operation of a doubly-linked list is to iterate over the list.
B)The least expensive operation of a doubly-linked list is to retrieve an arbitrary element.
C)The least expensive operation of a doubly-linked list is to add an element in the middle.
D)All of these operations have the same time cost.

Question

Quizplus · Accepted Answer

Adding an element in the middle of a doubly-linked list is the least expensive operation when the iterator is already at the correct location, as it only involves updating the pointers of the neighboring nodes, which is an O(1) operation. Iterating over the list or retrieving an arbitrary element can be more costly, especially in large lists, as it may require traversing multiple nodes.

Linked List Operations That Were Studied Included Adding/removing an Element