Top Data Structure Interview Questions & Answers | Get Started7 min readReading Time: 5 minutes
Have you ever wondered, how data is stored and organized in the databases? It’s possible only due to the data structure. You can organize the data and make it available at any point in time. If you are looking to grab a job in the top product-based companies like Google, Microsoft, Amazon, Apple Inc, etc, you need to have a strong data structure foundation. In this article, we will be discussing various data structure interview questions to help you. In fact, these questions and answers will help you get an overview of the interview. If you can master the basics, there will be enough opportunity to land into your dream job.
This blog will help you get an insight into the data structure interview. Furthermore, we have tried to give you an overview from basics to advanced levels to make you feel comfortable during the interview. In addition to this, we will give you a link to a brief overview of programmatic questions. They are also asked during the interview. To sum up, the main purpose of this blog is to guide you through every possible stage of data structure interview.
Also, find a list of C Programming Interview Questions and answers with programming examples for beginners and professionals.
Data Structure Interview Questions:
- Describe Data Structure.
- Tell us about various operations performed on different data structure.
- Discuss how array varies from a linked list.
- Discuss the application of Stack.
- Describe the types of linked lists.
- Discuss in detail about Binary Trees.
- List the types of trees.
- Which Data Structure suits most in tree construction?
- What are the advantages of Heap over Stack?
- What is Data Abstraction?
- How does a selection sort work for an array?
- How do signed and unsigned numbers affect memory?
- What are the dynamic data structures?
- What is a graph?
- Describe an AVL tree.
- How do you search for a target key in a linked list?
- What are the different Sort techniques in Data Structures?
- What is the difference between File Structure & Storage Structure?
- Which Data Structure is used in RDBMS, Network Data Model, Hierarchical Data Structure?
Data Structure Interview Questions and Answers:
The answers here will boost your preparation in addition to providing an overview.
Linear Data Structure
1. Describe Data Structure?
Data Structure is a process to organize and manipulate data. In addition to this, it also describes the relationship between them. Furthermore, it is a central part of many computer science algorithms as programmers find it easy to handle data inefficient way.
2. Tell us about various operations performed on different data structure?
The following operations are performed on different data structures.
Insertion is used to add a new data item whereas deletion is used to delete existing data from a given set. Similarly, traversal is used to access each data. Moreover, searching is used to find out the location of an existing data item in the set whereas sorting is used to arrange data in some order for its proper organization and usage.
3. Discuss how array varies from a linked list?
The array has fixed size whereas the linked list varies in size. Moreover, arrays have better cache locality which makes a big difference in performance. In fact, linked lists don’t allow random access. However, one can easily perform insertion and deletion on a linked list whereas it is difficult in an array.
4. Discuss the application of Stack?
A stack is a linear data structure based on order LIFO (Last In First Out) or FILO (First In Last Out).
The basic operations carried out on Stack are Push, Pop & Peek.
Application of Stack:
a. Infix to postfix conversion.
b. Reverse a String.
c. Implement two stacks an array
d. Check for balanced parentheses in an expression
5. Describe the types of linked lists?
The linked list is a linear data structure where every element is a separate object.
You may also like to watch the complete video on Data Structure Interview Questions:
Linked list Types:
a. Single linked lists:
Every node stores address or reference of the next node in the list. Similarly, the last node has the next address or reference.
b. Doubly linked lists
There are two references associated with each node. One reference points to the next node whereas the other one points to the previous one.
c. Circular linked lists
Here all nodes are connected to form a circle. In fact, there is no NULL at the end. egs: 1->2->3->1 [The next pointer of the last node is pointing to the first].
Related Post: Top 25 SQL Interview Questions That You Must Prepare
Non-linear Data Structure
6. Discuss in detail about Binary Trees?
It is a finite set of elements that is either empty or further divided into sub-trees. In other words, it is also called a non-linear data structure. One can call the child node on left as ‘left child node’ whereas the child node on right as ‘right child node’.
There are three types of Binary Trees:
a. Full binary tree
b. Complete binary tree
c. Threaded binary tree
7. List the types of trees?
Given below is the list of the types of trees:
a. General Tree
b. Binary Tree
c. Binary Search Tree
d. Expression Tree
8. Which Data Structure suits most in tree construction?
Queue data structure suits most in tree construction
9. What are the advantages of Heap over Stack?
Heap is more flexible than stack. Furthermore, it is durable than the stack. However, Stack allocates memory very fast though than the heap. There is a dynamic allocation of memory for the heap.
10. What is Data Abstraction?
Data abstraction is a process to break down complex data problems into manageable chunks. This helps in better operation and storage of data.
11. How does a selection sort work for an array?
Here, subscript zero contains the smallest element. In other words, the smallest element gets the first position. Similarly, the second smallest elements get the second position and so on.
12. How do signed and unsigned numbers affect memory?
A signed 8‑bit number has a range of (0–255) whereas an unsigned 8‑bit number has a range of ‑128 to 127. Similarly, the Unsigned 8‑bit number has all the bits available.
13. What are the dynamic data structures?
When a program runs, the dynamic data structures expand and contract. In other words, it can adjust as per the size of the data.
14. What is a graph?
A graph is a non-linear data structure that contains nodes and edges.
Graphs are used to represent networks which include path in a city or telephone networks, etc. Similarly, they are used in social networks like Linked In, Facebook or Twitter, etc.
15. Describe an AVL tree?
AVL tree is used to balance the existing binary search tree. In fact, it is always in a state of partially balanced.
16. How do you search for a target key in a linked list?
You can search for a target key using a sequential search in a linked list. Firstly, each node is traversed and compared with the target key. Then, the different one follows the link to the next node.
17. What are the different Sort techniques in Data Structures?
The different types of sort techniques in data structures are listed below:
a. Buble sort
b. Selection sort
c. Merge sort
d. Insertion sort
Data Structure Interview Questions and Answers on Files and Databases:
18. What is the difference between File Structure & Storage Structure?
If you write a data in the file and save that file in the hard disk or any other external device, the data will remain intact until it is deleted manually. To sum up, this act of saving data in a file on an auxiliary memory is called a file structure.
Every variable and constants have memory allocated in the main memory called a storage structure.
19. Which Data Structure is used in RDBMS, Network Data Model, Hierarchical Data Structure?
RDBMS uses an array data structure whereas Network Data Model uses graph and Hierarchical Data Structure uses tree data structures.
Data Structure is the most important topic in computer science. Almost all the product based companies that pay you a higher salary expect you to be proficient in it. To sum up, you have to give more time. In fact, a data structure is the foundation of every programming language and software, as well as, hardware. Hence, if you can master it, cracking the data structure interview will be a piece of cake.