Question

Consider a QUEUE implemented by doubly linked cells, and containing N elements. The ENQUE operation has worst-case time complexity of...

a. O(1)
b. O(log N)
c. O(N)
d. O(N²)

Answer 1

The worst-case time complexity of the ENQUE operation in a doubly linked list implementation of a queue with N elements is O(1).

Step-by-step explanation:

The worst-case time complexity of the ENQUE operation in a doubly linked list implementation of a queue with N elements is O(1).

When adding an element to the back of the queue, the ENQUE operation takes constant time, regardless of the number of elements already in the queue. This is because the doubly linked list allows direct access to both the head and tail of the list, enabling efficient insertion at the back.

Therefore, the time complexity of ENQUE does not depend on N, making the answer O(1).