Data Structure MCQs

Software is defined as _

A. a) set of programs, documentation & configuration of data
B. b) set of programs
C. c) documentation and configuration of data
D. d) None of the mentioned
Correct answer is: A. a) set of programs, documentation & configuration of data
Breakdown of the definition:

Programs: These are the executable instructions that the computer follows to perform tasks.

Documentation: This includes user manuals, technical specifications, and other written materials that explain how to use and maintain the software.

Configuration data: This refers to the data that determines how the software behaves, such as settings, preferences, and database information.

Together, these components form a complete software package that can be used to solve specific problems or perform specific functions.

Which of the following is not the type of queue?

A. a) Priority queue
B. b) Circular queue
C. c) Single ended queue
D. d) Ordinary queue
Correct answer is: C. c) Single ended queue
Why "Single-ended queue" is not a type of queue?

A queue is inherently a double-ended data structure.

It has two primary operations: enqueue (adding to the rear) and dequeue (removing from the front).

The term "single-ended queue" is a contradiction.

If it were single-ended, it would essentially be a stack, not a queue.

Therefore, among the given options, single-ended queue is not a valid type of queue.

The other options are valid queue types:

Priority queue: Elements have priorities, and the highest priority element is dequeued first.

Circular queue: The rear and front pointers wrap around to the beginning of the array when they reach the end.

Ordinary queue: The standard queue implementation with a front and rear pointer.

Which of the following tree data structures is not a balanced binary tree?

A. a) Splay tree
B. b) B-tree
C. c) AVL tree
D. d) Red-black tree
Correct answer is: B. b) B-tree
hy B-trees are not balanced binary trees

B-trees are indeed not balanced binary trees.

Key difference: While they are balanced, they are not binary trees.

Multiple children: Unlike binary trees, which have at most two children per node, B-trees can have multiple children (typically a minimum number defined by the order of the B-tree).

Efficiency: B-trees are designed for efficient storage and retrieval of large datasets on disk, where reading and writing data from disk is relatively slow. By allowing multiple children per node, B-trees can reduce the number of disk accesses required for search, insert, and delete operations.

In summary, while B-trees maintain balance properties to optimize performance, they deviate from the strict binary structure of binary trees.

The other options:

Splay trees, AVL trees, and Red-black trees are all types of balanced binary trees, meaning they have specific rules to maintain balance and ensure efficient operations.

What is a bit array?

A. a) Data structure that compactly stores bits
B. b) Data structure for representing arrays of records
C. c) Array in which elements are not present in continuous locations
D. d) An array in which most of the elements have the same value
Correct answer is: A. a) Data structure that compactly stores bits
Efficiency: It's designed to efficiently store boolean values (0 or 1) by utilizing individual bits instead of entire bytes or words.

Memory savings: This approach significantly reduces memory usage compared to traditional arrays that store each element as a complete byte or larger data type.

Applications: Bit arrays are commonly used in various algorithms and data structures, such as bloom filters, bitmaps, and set representations.

Essentially, a bit array is like an array, but instead of storing elements like integers or characters, it stores individual bits.

Which of the following application makes use of a circular linked list?

A. a) Recursive function calls
B. b) Undo operation in a text editor
C. c) Implement Hash Tables
D. d) Allocating CPU to resources
Correct answer is: D. d) Allocating CPU to resources
ircular linked lists are particularly well-suited for scenarios where a cyclical or repetitive pattern is involved. In the context of CPU allocation, this is precisely the case.

Round-robin scheduling: This is a common algorithm used to allocate CPU time to multiple processes.

Circular nature: A circular linked list forms a loop, perfectly representing the cyclic nature of round-robin scheduling.

Efficient iteration: The circular structure allows for easy traversal from one process to the next without the need for special end-of-list checks.

By maintaining a circular linked list of processes, the operating system can efficiently cycle through them, granting each process a time slice of CPU time in turn. Once the last process is served, the list wraps back to the beginning, ensuring fairness and equal opportunity for all processes.

Would you li

Which data structure is based on the Last In First Out (LIFO) principle?

A. a) Tree
B. b) Linked List
C. c) Stack
D. d) Queue
Correct answer is: C. c) Stack
Explanation:

LIFO means the last element added to the stack is the first one to be removed.

Imagine a stack of plates. The last plate you put on the stack is the first one you take off.

This behavior is essential in many applications, such as function calls, expression evaluation, and backtracking algorithms.

Key operations of a stack:

Push: Adds an element to the top of the stack.

Pop: Removes the top element from the stack.

Peek: Returns the top element without removing it.

isEmpty: Checks if the stack is empty.

Which of the following points is/are not true about Linked List data structure when it is compared with an array?

A. a) Random access is not allowed in a typical implementation of Linked Lists
B. b) Access of elements in linked list takes less time than compared to arrays
C. c) Arrays have better cache locality that can make them better in terms of performance
D. d) It is easy to insert and delete elements in Linked List
Correct answer is: B. b) Access of elements in linked list takes less time than compared to arrays
Access of elements in linked list takes less time than compared to arrays is not true.

Explanation:

Arrays provide random access to elements. This means you can directly access any element by its index in constant time (O(1)).

Linked lists provide sequential access to elements. To access a specific element, you need to traverse the list from the beginning, one node at a time. This takes linear time (O(n)), where n is the number of elements in the list.

Therefore, accessing elements in a linked list is generally slower than in an array.

The other options are true:

a) Random access is not allowed in a typical implementation of Linked Lists: This is correct.

c) Arrays have better cache locality that can make them better in terms of performance: This is true due to the way arrays store elements contiguously in memory.

d) It is easy to insert and delete elements in Linked List: This is generally true, especially when compared to arrays, where shifting elements might be required.

The prefix form of A-B/ (C * D ^ E) is?

A. a) -A/B*C^DE
B. b) -A/BC*^DE
C. c) -ABCD*^DE
D. d) -/*^ACBDE
Correct answer is: A. a) -A/B*C^DE
Understanding Prefix Notation

In prefix notation, the operator precedes its operands.

The order of evaluation is from right to left.

Breaking Down the Expression

Given the infix expression: A - B / (C * D ^ E)

To convert it to prefix, we need to follow these steps:

Handle Parentheses:

We start with the innermost parentheses: (C * D ^ E)

Converting this to prefix: * ^ CD E

Handle Division:

The expression becomes: A - B / (* ^ CD E)

Converting it to prefix: - A / B * ^ CD E

Final Prefix Expression:

The complete prefix expression is: -A / B * ^ CD E

Therefore, the correct prefix form of the given infix expression is -A / B * ^ CD E.

The data structure required for Breadth First Traversal on a graph is?

A. a) Array
B. b) Stack
C. c) Tree
D. d) Queue
Correct answer is: D. d) Queue
A queue is the essential data structure for Breadth-First Search (BFS) traversal on a graph.

Why a Queue?

FIFO (First In, First Out) principle: This is crucial for exploring nodes level by level. The first node added to the queue is the first one to be visited.  

Efficient enqueue and dequeue operations: The queue allows for quick insertion and removal of nodes, which is necessary for BFS.

How it works:

Enqueue the starting node: Add the initial node to the queue.

Dequeue a node: Remove the front node from the queue and visit it.

Enqueue neighbors: Add all unvisited neighbors of the dequeued node to the queue.  

Repeat steps 2 and 3: Continue until the queue is empty.

By using a queue, BFS ensures that all nodes at a given depth are visited before moving to the next level, resulting in a breadth-wise exploration of the graph.

Which of the following statement(s) about stack data structure is/are NOT correct?

A. a) Top of the Stack always contain the new node
B. b) Stack is the FIFO data structure
C. c) Null link is present in the last node at the bottom of the stack
D. d) Linked List are used for implementing Stacks
Correct answer is: B. b) Stack is the FIFO data structure
Stack is the FIFO data structure is the incorrect statement.

Explanation:

Stack follows the LIFO (Last In, First Out) principle. This means the last element added to the stack is the first one to be removed.

FIFO (First In, First Out) is the characteristic of a queue data structure, not a stack.

The other options are correct:

a) Top of the Stack always contains the new node: This is true, as new elements are added to the top of the stack.

c) Null link is present in the last node at the bottom of the stack: This is typically true in a linked list implementation of a stack, where the bottom node points to null to indicate the end of the stack.

d) Linked List are used for implementing Stacks: This is a common way to implement stacks.

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