Queues

What is a queue in data structures?

• A queue is a type of tree structure used for hierarchical data.

• A queue is a data structure that follows the LIFO principle.

• A queue is a linear data structure that follows the FIFO principle.

• A queue is a non-linear data structure that allows random access.

How does a queue differ from a stack?

• A queue follows FIFO, while a stack follows LIFO.

• A queue allows random access, while a stack does not.

• A queue is used for depth-first search, while a stack is used for breadth-first search.

• A stack can grow dynamically, while a queue has a fixed size.

What are the main operations performed on a queue?

• push and pop

• add and take

• insert and remove

• The main operations performed on a queue are enqueue and dequeue.

What is a circular queue and how does it work?

• A circular queue is a data structure that uses a fixed-size array in a circular manner to efficiently manage elements.

• A circular queue is a data structure that only allows elements to be added at the end.

• A circular queue is a type of linked list that allows dynamic resizing.

• A circular queue is a linear data structure that uses a stack to manage elements.

Describe a real-world example of a queue.

• People waiting in line at a grocery store checkout.

• Animals in a zoo enclosure.

• Students sitting in a classroom during a lecture.

• Cars waiting at a traffic light.

What is the time complexity of enqueue and dequeue operations?

• O(n) for both enqueue and dequeue in a linked list implementation

• O(1) for enqueue and O(1) for dequeue in a simple array implementation

• O(n) for both enqueue and dequeue in a circular array implementation

• O(1) for both enqueue and dequeue in a linked list implementation; O(1) for enqueue and O(n) for dequeue in a simple array implementation; O(1) for both in a circular array implementation.

How can queues be implemented using arrays?

• Queues can be implemented using a single pointer for both insertion and removal.

• Queues require a fixed size and cannot be dynamic.

• Queues can be implemented using arrays by using two pointers: 'front' for removal and 'rear' for insertion.

• Queues can only be implemented using linked lists.

Suppose a circular queue of capacity (n – 1) elements is implemented with an array of n elements. Assume that the insertion and deletion operation are carried out using REAR and FRONT as array index variables, respectively. Initially, REAR = FRONT = 0. The conditions to detect queue full and queue empty are

• Full: (REAR+1) mod n == FRONT, empty: REAR == FRONT

• Full: (REAR+1) mod n == FRONT, empty: (FRONT+1) mod n == REAR

• Full: REAR == FRONT, empty: (REAR+1) mod n == FRONT

• Full: (FRONT+1) mod n == REAR, empty: REAR == FRONT

In a circular queue, how do you increment the rear end of the queue?

• rear++

• (rear+1) % Number of Item

• (rear % Number of Item)+1

• rear–

If elements are inserted in the order -10,-2,-3,4,-1,6 then to delete value -3 how many dequeue operations are required?