Queues

Question 1

What is an Abstract Data Type (ADT)?

Answer 1

An ADT is a mathematical model for data types where the data type is defined by its behavior from the point of view of a user, specifically the operations that can be performed on it.

Question 2

What is a queue?

Answer 2

A queue is an ADT that represents a collection of elements in which elements are added at one end (the rear) and removed from the other end (the front), following the First-In-First-Out (FIFO) principle.

Question 3

True or False: In a queue, the last element added is the first one to be removed.

Answer 3

False

Question 4

What are the primary operations of a queue?

Answer 4

The primary operations of a queue are enqueue (adding an element), dequeue (removing an element), and peek (viewing the front element without removing it).

Question 5

Fill in the blank: In a queue, elements are added at the _____ and removed from the _____.

Answer 5

rear; front

Question 6

What is the main difference between a queue and a stack?

Answer 6

A queue follows the FIFO principle, while a stack follows the Last-In-First-Out (LIFO) principle.

Question 7

What is a circular queue?

Answer 7

A circular queue is a linear data structure that uses a single, fixed-size array in a circular way to efficiently utilize space by wrapping around.

Question 8

True or False: A circular queue can lead to wasted space if not implemented correctly.

Answer 8

True

Question 9

What is a priority queue?

Answer 9

A priority queue is an abstract data type where each element has a priority assigned to it, and elements are dequeued based on their priority rather than their order in the queue.

Question 10

How does a priority queue differ from a regular queue?

Answer 10

In a priority queue, elements are removed based on priority, whereas in a regular queue, elements are removed in the order they were added.

Question 11

What data structure is commonly used to implement a priority queue?

Answer 11

A binary heap is commonly used to implement a priority queue.

Question 12

Fill in the blank: The operation to remove an element from a queue is called _____

Answer 12

dequeue

Question 13

What is the initial condition of an empty queue?

Answer 13

The queue is said to be empty when there are no elements present in it.

Question 14

What happens when you try to dequeue from an empty queue?

Answer 14

It typically results in an underflow error, indicating that there are no elements to remove.

Question 15

What is the purpose of the peek operation in a queue?

Answer 15

The peek operation allows you to view the front element of the queue without removing it.

Question 16

True or False: A queue can be implemented using arrays.

Answer 16

True

Question 17

What is the main disadvantage of using an array to implement a queue?

Answer 17

The main disadvantage is that it can lead to wasted space if elements are removed from the front and the array size is fixed.

Question 18

What is a dequeue?

Answer 18

A dequeue (double-ended queue) is a data structure that allows insertion and deletion of elements from both the front and rear ends.

Question 19

How do you determine if a queue is full?

Answer 19

In a fixed-size array implementation, a queue is full when the number of elements equals the maximum capacity of the array.

Question 20

What is a blocking queue?

Answer 20

A blocking queue is a type of queue that causes the thread to wait until the queue is not empty when trying to dequeue or until it is not full when trying to enqueue.

Question 21

True or False: Queues can only store homogeneous data types.

Answer 21

False

Question 22

What is the significance of the ‘front’ pointer in a queue implementation?

Answer 22

The ‘front’ pointer tracks the first element in the queue for efficient access during dequeue operations.

Question 23

Fill in the blank: A queue is often used in _____ algorithms for managing tasks.

Answer 23

scheduling

Question 24

What is the common application of a queue in computer science?

Answer 24

Queues are commonly used in scenarios like print job management, task scheduling, and breadth-first search algorithms.

Question 25

What is the main advantage of using a linked list to implement a queue?

Answer 25

The main advantage is dynamic sizing, allowing the queue to grow and shrink as needed without wasting space.

Question 26

What is the main drawback of using a linked list for a queue?

Answer 26

The main drawback is the overhead of additional memory for storing pointers.

Question 27

What does FIFO stand for?

Answer 27

FIFO stands for First-In-First-Out.

Question 28

In which scenarios would you prefer a priority queue over a regular queue?

Answer 28

You would prefer a priority queue in scenarios where tasks need to be processed based on their importance rather than their arrival order.

Question 29

What is a queue in data structures?

Answer 29

A queue is a linear data structure that follows the First In First Out (FIFO) principle.

Question 30

Which operator is commonly used to add an element to a queue?

Answer 30

The enqueue operator is used to add an element to a queue.

Question 31

True or False: The dequeue operator removes the last element from a queue.

Answer 31

False: The dequeue operator removes the first element from a queue.

Question 32

Fill in the blank: The _____ operator is used to retrieve the front element of a queue without removing it.

Answer 32

peek

Question 33

What does the term 'FIFO' stand for in queue operations?

Answer 33

First In First Out

Question 34

In a queue, what happens when the enqueue operation is performed on a full queue?

Answer 34

It results in an overflow condition.

Question 35

What is the purpose of the dequeue operation?

Answer 35

To remove and return the front element of the queue.

Question 36

Which operator checks if a queue is empty?

Answer 36

The isEmpty operator checks if a queue is empty.

Question 37

True or False: A circular queue is a variation of a regular queue that overcomes the limitation of fixed size.

Answer 37

True

Question 38

Fill in the blank: A queue can be implemented using an _____ or a linked list.

Answer 38

array

Question 39

Which operator is used to remove an element from the rear of a queue in a deque?

Answer 39

pop_back

Question 40

What is a priority queue?

Answer 40

A priority queue is a data structure where each element has a priority, and elements are dequeued based on their priority rather than their order in the queue.

Question 41

True or False: In a priority queue, the element with the highest priority is dequeued first.

Answer 41

True

Question 42

What is the main difference between a queue and a stack?

Answer 42

A queue follows FIFO, while a stack follows Last In First Out (LIFO).

Question 43

Fill in the blank: In a queue, the _____ operation retrieves the element at the front without removing it.

Answer 43

peek

Question 44

Which operator would you use to clear all elements from a queue?

Answer 44

The clear operator is used to remove all elements from a queue.

Question 45

What is the main use case for a queue in programming?

Answer 45

Queues are commonly used in scenarios like task scheduling, breadth-first search, and handling requests in a server.

Question 46

True or False: A queue can only store elements of the same data type.

Answer 46

False: A queue can store mixed data types depending on the implementation.

Question 47

What does the enqueue operation return upon success?

Answer 47

Typically, it returns a confirmation or success status.

Question 48

What happens during a dequeue operation if the queue is empty?

Answer 48

It results in an underflow condition.

Question 49

Fill in the blank: In a circular queue, the rear pointer wraps around to the _____ when it reaches the end of the array.

Answer 49

front

Question 50

Which operator indicates the current size of a queue?

Answer 50

The size operator returns the current number of elements in the queue.

Question 51

What is the primary advantage of a circular queue over a linear queue?

Answer 51

It efficiently utilizes space by reusing empty slots.

Question 52

Fill in the blank: In a queue, elements are added at the _____ and removed from the _____ end.

Answer 52

rear; front

Question 53

What type of queue allows insertion and deletion from both ends?

Answer 53

Deque (Double-ended queue)

Question 54

True or False: A queue can be implemented using a linked list.

Answer 54

True

Question 55

What is the primary disadvantage of using an array-based queue?

Answer 55

Fixed size leading to overflow if maximum capacity is reached.

Question 56

Fill in the blank: The _____ operation is used to check the element at the end of the queue.

Answer 56

back