Corporate Experience Software Developer

10 Data Structure Interview Questions for Freshers & Experienced

Whiteboard interviews are standard in today’s job market. In most cases, you may expect the questions to be quite basic. Whether you’re looking for an entry-level job or an experienced role, Data structures are a hot topic. Being a Developer advocate myself, I know how much people focus on DSA for interviews and pass through various coding and interview questions.

Your next data structure interview may leave you wondering what questions to expect. Remember that data structure interviewers aren’t trying to trick you and don’t demand perfection. Still, it’s their opportunity to establish your understanding before they invest in your job before the interview process begins.

Check out these data structure interview questions and answers for freshers and experienced aspirants as you may be asked and need to be prepared for in your next programming interview by following along here.

Corporate Experience Software Developer
Data Structures interview questions

Significance of data structure concepts

Many Computer Science graduates downplay the significance of understanding data structures and algorithms because they believe they are complicated, unnecessary, or a waste of time. However, when they begin searching for a job in the real world, they receive a harsh reality check. Questions about DSA are frequently used by large corporations such as Amazon, Google, and Microsoft to test job seekers’ problem-solving capabilities.

As a result, familiarize yourself with data structures and algorithms fundamentals before attending a technical interview. Algorithms and their attributes have real-world significance. 

10 data structure interview questions with answers 

For Freshers

1. Define Data structure?

Ans: The data structure is simply a way to organize data in a computer. It’s not a language. It’s merely a method you can implement in C, C++, and Java.

2. Why is a linked list better than an array?


ArraysLinked list
The array index provides random access to array elements.In a linked list, it is impossible to access items at random. Sequential access is required to all of the elements.
Memory stores data in a logical sequence rather than in random areasPointers create a reference for a new element that can be kept wherever you choose.

3. In terms of data structures, what are the possible types?

Ans: Interviewers regularly ask this type of question, expecting you to give a clear answer. In the world of data, there are two sorts of structures:

  • Linear data structures: These are those in which the elements are arranged to appear consecutive and orderly. As an illustration, consider Array and Linked list.
  • Non-linear data structures: Each item or element in a non-linear arrangement is connected to two or more other things in a data structure known as non-linear. There is no sequential organization to the data. 

4. In what ways are data structures used?

Ans: Data is organized in data structures to be easy to utilize. The following are among the many practical uses of data structures:

  • You are keeping data organized in a table format. Let’s say you want to find out how to get in touch with someone. Arrays are used to do this.
  • It is very helpful for arrays in image and speech processing.
  • Music players and picture sliders use linked Lists to navigate between items.
  • In computing, a Queue is used to schedule tasks and organize data packets for transmission.
  • Hashing algorithms are used in technologies such as Blockchain and cryptography.
  • Practising matrices to represent data, create graphs, and do statistical analysis is expected.

5. What exactly is a queue? What distinguishes it from the stack?

Ans: The FIFO (First In, First Out) strategy for accessing elements is used by queues, which are a linear structure. A queue’s basic operations include deque, enqueue, the front, and the rear. You can use an array or linked list to implement a queue. Remove the item that you added the most recently. While this may seem an obvious rule of thumb, it’s the opposite in a queue.

6. Define Dynamic Arrays?

Ans: A dynamic array auto-resizes. Dynamic arrays grow as you add elements. Arrays’ fixed size means you must define the number of elements ahead of time. 

For Experienced

1. What’s the fastest sorting algorithm? Why?

Ans: Each sorting method is intended for a specific data collection and structure. QuickSort is the fastest algorithm since it works well with most inputs.

Advantages over alternative sorting algorithms:

  • Cache-efficient: reads and partitions input linearly. It maximizes every cache load.
  • Efficient even with unpredictable input order in worst-case scenarios.
  • Easily adapts to sorted inputs.

2. What’s Queue Complexity Analysis?


  • Queues allow random access by moving the first item to the back. Repeat this to access any queue element. Access is O (n).
  • Finding a value in a queue involves iteration—o search (n).
  • Inserting into a queue can only happen towards the back, like ordering a Double-Double at In’ n Out. Queue insertion is O (1), assuming an efficient queue.
  • Deleting from a queue happens first. Queue deletion is O. (1), assuming an efficient queue.

3. How does variable declaration impact memory allocation?

Ans: Variable data types determine how much space or memory is used. Let’s illustrate this with an example. If the variable is specified as an integer, 32 bits of memory are allocated. Variable memory is given based on its data type.

4. How do you make a queue with a stack?


  • A queue may be created using two stacks. The first member is always at the top to complete the queue’s enqueue action.
  • To enqueue an item, move all elements from the beginning stack to the second stack, push the item, and then send all components back to the first stack.
  • From the 1st stack, return the top item to dequeue an item.

Final words

Data structures interview questions are crucial for Data Science and Java-based roles. Data structures and algorithms will help you distinguish from other contenders. In any DSA interview, these are a few questions you may expect to be asked about the stack, the queue, the array, the linked list, the tree, and the graph.

Still having doubts? Don’t panic. Register for Simplilearn online learning platform to learn advanced tactics from industry experts.

About Atulmaharaj

A seasoned blogger and a content marketer for close to a decade now. I write about Food, Technology, Lifestyle, Travel, and Finance related posts. Blogging brings me joy and the best part is I get to read and e-meet so many amazing bloggers! PS: I'm also the founder for :) Favorite Quote: "Traveling is like reading a book, one who hasn't traveled, hasn't turned a page.

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