Stacks and Queues: A Comprehensive Guide for Computer Science Students

Question 1

Which of the following statements about stacks and queues is **false**?

Accepted Answer

Stacks can be implemented using only arrays.

Answer

Stacks follow the Last-In-First-Out (LIFO) principle.

Answer

Queues follow the First-In-First-Out (FIFO) principle.

Answer

Queues can be implemented using both linked lists and arrays.

Question 2

Which data structure adheres strictly to the 'last-in, first-out' (LIFO) principle?

Accepted Answer

Stack

Answer

Queue

Answer

Array

Answer

Linked List

Question 3

Which of the following applications leverages the LIFO property of stacks?

Accepted Answer

Managing function calls

Answer

Tracking web browsing history

Answer

Prioritizing tasks in scheduling

Answer

Storing messages in a queue

Question 4

When implementing a priority queue, which data structure is typically used internally?

Accepted Answer

Heap

Answer

Array

Answer

Linked list

Answer

Stack

Question 5

In a singly linked list implementation of a queue, what is the purpose of a sentinel node?

Accepted Answer

It identifies the beginning and end of the queue.

Answer

It prevents null pointer exceptions during operations.

Answer

It facilitates priority scheduling within the queue.

Answer

It stores the current number of elements in the queue.

Question 6

In a queue, which operation removes and returns the oldest element?

Accepted Answer

dequeue()

Answer

enqueue()

Answer

add()

Answer

pop()

Question 7

Which real-world scenario best exemplifies a stack's functionality?

Accepted Answer

Undoing the last action in a text editor

Answer

Customers waiting in a checkout line

Answer

Storing a list of recently visited websites

Answer

Managing tasks in a to-do list

Question 8

What key distinction differentiates stacks from queues?

Accepted Answer

Stacks follow LIFO (Last-In-First-Out) while queues follow FIFO (First-In-First-Out)

Answer

Queues follow LIFO while stacks follow FIFO

Answer

Stacks and queues both adhere to LIFO

Answer

Stacks and queues both adhere to FIFO

Question 9

Which everyday situation serves as an illustration of a queue?

Accepted Answer

A line of people waiting for a bus

Answer

A stack of plates

Answer

A deck of cards

Answer

A grocery list

Question 10

When adding an element to a stack, which operation is employed?

Accepted Answer

Push

Answer

Pop

Answer

Enqueue

Answer

Insert

Question 11

In a queue, which operation retrieves and removes the element that has been waiting the longest?

Accepted Answer

Dequeue

Answer

Push

Answer

Pop

Answer

Remove

Question 12

When searching for an element in a stack, what is the time complexity?

Accepted Answer

O(n)

Answer

O(1)

Answer

O(log n)

Answer

O(n^2)

Question 13

Which data structure is suitable for implementing a priority queue?

Accepted Answer

Binary heap

Answer

Array

Answer

Linked list

Answer

Hash map

Question 14

Which of the following operations is not supported by a stack data structure?

Accepted Answer

Traversal

Answer

Push

Answer

Pop

Answer

Peek

Question 15

For a queue data structure, the time complexity of the enqueue operation is:

Accepted Answer

O(1)

Answer

O(n)

Answer

O(log n)

Answer

O(n^2)

Question 16

For scenarios where elements need to be processed in the sequence they were received, which data structure is most appropriate?

Accepted Answer

Queue

Answer

Stack

Answer

Linked list

Answer

Array

Question 17

The fundamental distinction between a stack and a queue lies in:

Accepted Answer

Order of element access

Answer

Underlying storage mechanism

Answer

Type of elements stored

Answer

Implementation complexity

Question 18

Consider a stack implemented using an array. Where is the top element of the stack typically stored?

Accepted Answer

End of the array

Answer

Beginning of the array

Answer

Middle of the array

Answer

Depends on the specific implementation

Question 19

Which of the following operations is a fundamental characteristic of a stack data structure?

Accepted Answer

Last-In-First-Out (LIFO)

Answer

Adding elements at any position

Answer

First-In-First-Out (FIFO)

Answer

Searching for elements in constant time

Question 20

Which of the following scenarios commonly employs a queue data structure?

Accepted Answer

Managing tasks in a job scheduling system

Answer

Searching for data in a binary tree

Answer

Traversing a linked list in depth-first order

Answer

Storing elements in a heap data structure

Question 21

Consider a circular queue with a capacity of 5. If the queue is initially empty, what is the maximum number of elements that can be enqueued?

Accepted Answer

5

Answer

4

Answer

6

Answer

7

Question 22

Which of the following data structures is NOT suitable for representing a stack?

Accepted Answer

Hash table

Answer

Array

Answer

Linked list

Answer

Binary search tree

Question 23

Which of the following algorithms is commonly used to implement a priority queue?

Accepted Answer

Heap sort

Answer

Depth-first search (DFS)

Answer

Breadth-first search (BFS)

Answer

Quick sort

Question 24

What is a primary advantage of using a deque data structure?

Accepted Answer

Efficient insertion and deletion from both ends

Answer

Constant-time access to any element

Answer

Simplified implementation of queues and stacks

Answer

Reduced memory overhead compared to lists

Question 25

In a Last-In-First-Out (LIFO) data structure, the most recently added element is the first to be removed. Which data structure follows this principle?

Accepted Answer

Stack

Answer

Queue

Answer

Linked List

Answer

Array

Question 26

To obtain the value of the topmost element in a stack without removing it, which operation should be used?

Accepted Answer

Peek

Answer

Push

Answer

Pop

Answer

Enqueue

Question 27

Queues are commonly employed for which of the following purposes?

Accepted Answer

Organizing tasks in a first-in-first-out (FIFO) manner

Answer

Implementing a Depth-First Search

Answer

Managing memory allocation

Answer

Storing objects in a specific order

Question 28

Which data structure is most suitable for implementing an algorithm that requires backtracking?

Accepted Answer

Stack

Answer

Queue

Answer

Array

Answer

Linked List

Question 29

Which operation is not applicable to a queue?

Accepted Answer

Push

Answer

Enqueue

Answer

Dequeue

Answer

Peek

Question 30

In a practical scenario, which data structure would be most appropriate for managing customer requests in a call center?

Accepted Answer

Queue

Answer

Stack

Answer

Linked List

Answer

Hash Table

Question 31

When implementing a stack using an array, what is the time complexity of the push operation?

Accepted Answer

O(1)

Answer

O(n)

Answer

O(log n)

Answer

O(n^2)

Question 32

A Last-In, First-Out (LIFO) data structure is known as a:

Accepted Answer

Stack

Answer

Queue

Question 33

The time complexity of a stack push operation is:

Accepted Answer

O(1)

Answer

O(n)

Question 34

A characteristic that is not associated with stacks is:

Accepted Answer

Random access

Answer

First-In, Last-Out

Question 35

Queues follow the principle known as:

Accepted Answer

First-In, First-Out

Answer

Last-In, First-Out

Question 36

How can a queue be used to create a basic task scheduler in an operating system?

Accepted Answer

Store tasks in the queue to be executed sequentially.

Answer

Store data in the queue for random access.

Answer

Create a stack data structure using the queue.

Answer

Implement a binary tree structure using the queue.

Question 37

In the context of a web server, which data structure, a stack or a queue, is more suitable for managing the incoming request queue? Explain your reasoning.

Accepted Answer

Queue (First-In-First-Out)

Answer

Stack (Last-In-First-Out)

Question 38

What is the defining characteristic of a stack data structure?

Accepted Answer

Last-In, First-Out (LIFO)

Answer

First-In, First-Out (FIFO)

Answer

Random access to elements

Answer

Fixed size

Question 39

What are the primary operations performed on a queue data structure?

Accepted Answer

Enqueue and Dequeue

Answer

Insert and Delete (at any position)

Answer

Push and Pop

Answer

Search and Retrieve

Question 40

Which of the following is a common application of a stack data structure?

Accepted Answer

Function call management

Answer

Breadth-first search

Answer

Message queuing

Answer

Database indexing

Question 41

What is the typical time complexity of the enqueue operation in a queue implemented using an array?

Accepted Answer

O(1)

Answer

O(n^2)

Answer

O(log n)

Answer

O(n)

Question 42

If a stack is implemented using an array, which of the following statements is true?

Accepted Answer

The top element of the stack is typically located at the end of the array.

Answer

The bottom element of the stack is always at the beginning of the array.

Answer

The stack can grow dynamically without any size limitations.

Answer

The stack can be accessed randomly like an array.

Question 43

What is a primary advantage of using a queue compared to a stack?

Accepted Answer

Queues maintain the First-In, First-Out (FIFO) order, which is crucial in scenarios where order of processing is important.

Answer

Queues provide random access to elements.

Answer

Queues are more efficient for storing large datasets.

Answer

Queues are more flexible in terms of implementation.

Question 44

Which of the following scenarios is a common application of a queue data structure?

Accepted Answer

Managing print jobs in a printer queue

Answer

Calculating the shortest path in a graph using Dijkstra's algorithm

Answer

Performing a binary search on a sorted array

Answer

Compressing data using Huffman coding

Question 45

What is a primary disadvantage of using a stack data structure?

Accepted Answer

Accessing elements in the middle of the stack directly is not possible.

Answer

Stacks are not suitable for managing function calls.

Answer

Stacks are inefficient for storing large amounts of data.

Answer

Stacks can be complex to implement compared to other data structures.

Question 46

What principle governs the order of element access in a stack?

Accepted Answer

Last In First Out (LIFO)

Answer

First In Last Out (FILO)

Answer

Last In Last Out (LILO)

Answer

First In First Out (FIFO)

Question 47

Which of these operations is NOT typically associated with a queue data structure?

Accepted Answer

Pop

Answer

Enqueue

Answer

Peek

Answer

Dequeue

Question 48

In which scenario would a stack be the most suitable data structure?

Accepted Answer

Implementing an undo feature in a text editor

Answer

Storing a collection of customer records sorted by last name

Answer

Managing print jobs on a network printer

Answer

Finding the shortest path in a graph

Question 49

What is the time complexity of inserting an element at the end of a queue implemented using a linked list?

Accepted Answer

O(1)

Answer

O(log n)

Answer

O(n)

Answer

O(n log n)

Question 50

Which data structure is used to evaluate postfix expressions?

Accepted Answer

Stack

Answer

Queue

Answer

Linked List

Answer

Binary Tree

Question 51

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

Accepted Answer

An exception or error is thrown

Answer

The program enters an infinite loop

Answer

The first element of the queue is returned

Answer

The queue remains unchanged

Question 52

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

Accepted Answer

Efficient use of memory space

Answer

Easier traversal

Answer

Faster enqueue operations

Answer

Simpler implementation

Question 53

Which algorithm uses a queue to find the shortest path in an unweighted graph?

Accepted Answer

Breadth First Search (BFS)

Answer

Depth First Search (DFS)

Answer

Dijkstra's Algorithm

Answer

A* Search

Question 54

What is the maximum number of elements a stack of size 'n' can hold?

Accepted Answer

n

Answer

n+1

Answer

Unlimited

Answer

n-1

Question 55

In a priority queue, what determines the order in which elements are dequeued?

Accepted Answer

Priority assigned to each element

Answer

Data type of the elements

Answer

Random selection

Answer

Order of insertion