Question

A data structure in which elements can be inserted or deleted at / from both ends but not in the middle is

• A. Priority queue
• B. Dequeue
• C. Circular queue
• D. Queue

Hint:

The name "Dequeue" is a contraction of "Double-Ended Queue". This name itself tells you its main feature: it's a queue where you can operate on both ends.

Answer 1

The Correct Option is B

Step 1: Analyze the properties of the described data structure. The key property is the ability to add and remove elements from \textit{both} the front and the back.
Step 2: Evaluate the options.

(A) Priority queue: Elements are removed based on priority, not position.
(B) Dequeue (Double-Ended Queue): This data structure is specifically designed to allow insertion and deletion at both ends. This matches the description.
(C) Circular queue: A standard queue implemented in a fixed-size array, where the back can wrap around to the front. It still follows the FIFO (First-In, First-Out) principle for insertion (at back) and deletion (at front).
(D) Queue: A standard queue follows FIFO. Elements are inserted at one end (rear) and deleted from the other end (front).
The data structure that allows operations at both ends is the Dequeue.