Differentiate between: (i) Linear Queue and Circular Queue (ii) A Queue and a

Q. Differentiate between: (i) Linear Queue and Circular Queue (ii) A Queue and a Deque.

Answer :-

(a) 

Linear Queue

A queue is a linear data structure in which elements are inserted from the rear and removed from
the front. A linear queue is a basic implementation of a queue where elements are stored in a straight line or sequence, and the insertion and deletion of elements take place at either end of the sequence.

Circular Queue

A circular queue is a more advanced form of a queue, in which elements are stored in a circular manner instead of a straight line. In a circular queue, the first element is adjacent to the last element, and the queue can be visualized as a circular buffer.

1. In a linear queue, elements are inserted at one end and deleted from the other end, whereas in a circular queue, the elements are inserted and removed in a circular manner, i.e., the last element is adjacent to the first element.

2. In a linear queue, memory usage is not optimized, as the elements are stored in a straight line. In a circular queue, memory usage is optimized because it uses a circular buffer to store elements.

3. A linear queue is easy to implement and can be implemented using a simple array or linked list. A circular queue is slightly more complex to implement and requires a circular buffer data structure to store elements.

4. In a linear queue, there is a possibility of overflow or underflow, which requires special handling of the queue. In a circular queue, the possibility of overflow or underflow is eliminated, as the queue is circular and elements can wrap around to the beginning.

5. In terms of performance, a circular queue is more efficient than a linear queue for certain operations, such as insertion and deletion. This is because a circular queue has a constant time complexity for these operations, whereas a linear queue has a linear time complexity.

(b)

A Queue is a linear data structure that follows the First-In-First-Out (FIFO) principle, which means that the first element added to the queue will be the first one to be removed. A Queue has two ends: the front end, where elements are removed, and the rear end, where elements are added.

A Deque (Double Ended Queue) is also a linear data structure that allows the insertion and deletion of elements from both ends. This means that elements can be added or removed from either the front end or the rear end of the queue.

The main difference between a Queue and a Deque is that a Queue only allows insertion at the rear end and removal from the front end, while a Deque allows insertion and removal from both ends.