Top 10 Coding Interview Questions With Answers

Learning coding and getting a job in the field has become a trend. Coding interviews are specialised interviews for candidates looking for a position in coding. It involves basic and advanced coding interview questions which test candidates’ arithmetic and computer programming problems essential for coding and problem-solving tasks. Coding interview questions generally start with, ‘How did you develop an interest in coding,’ ‘What type of coding you are skilled in,’ ‘Where did you learn coding,’ etc. 

Also Read: Coding for Beginners: A Step-by-Step Guide

Tips to Answer Coding Interview Questions

Coding interviews are as much about problem-solving skills as they are about coding ability. Practice and preparation will boost your confidence and performance. Here are six tips to help you excel in coding interviews:

• Regular coding practice is essential. Solve a variety of problems to build your problem-solving skills and familiarity with different algorithms and data structures.
• Deeply understand the basics of algorithms, data structures, and time/space complexity. This foundation will help you approach complex problems more effectively.
• Break down the problem into smaller subproblems. Tackle each subproblem individually, then combine solutions to solve the main problem.
• Explain your thought process as you work through the problem. Interviewers value your reasoning and approach more than just the final solution.
• Test your code with sample inputs and edge cases. Once it works, consider optimizing it by reducing time complexity or improving code readability.
• Whether you solve the problem or not, communicate your thought process clearly. Even if you are stuck, sharing your approach might earn you partial credit.

Also Read: Handle Tough Interview Questions With Ease

Most Common Coding Interview Questions

Candidates appearing or preparing for a coding interview must keep themselves updated about the recent developments taking place in the field of coding as the interviewer might start the interview by asking ‘What are your views on the latest developments in coding?’ Or the interview might present a problem to you when your coding skills are required to solve it. 

Answering interview questions and showing your technical skills at the same time can be arduous. But as they say, every problem has a solution at its level, and so does a job interview or coding interview. Below we have divided the coding interview questions into two categories: Conceptual and Programming Questions.

1. What is data structure?

Answer: “A data structure is a collection of information stored in a computer’s memory or storage system to facilitate various operations and manipulation of that data. It defines how data is organised, accessed and managed and the relationships and operations that can be performed using that specific data.”

2. What is a Stack?

Answer: “A stack is a collection of various elements with two primary operations: Push and Pop. Push operations add an element to the top and pop operations remove the top element. Stacks perform operations on a LIFO basis, which stands for Last-In-First-Out.”

Also Read: Top 10 Questions Asked in a Full-Stack Developer Interview

3. What is a FIFO?

Answer one of the most important coding interview questions with ‘The concept of FIFO, which stands for First-In-First-Out, is commonly used in computing, especially in data structures and scheduling algorithms. FIFO is a principle that dictates that the first element added to a system should be the first one to be removed or processed. Through this, items are processed in the order in which they were added.”

4. What is a LIFO?

Answer: “LIFO is a concept used in computer programming, data structuring and memory management. It stands for Last-In-First-Out, and in this, the last system is added or pushed into a collection in the first one and the first one added is removed from the collection. LIFO is the opposite of FIFO.”

Also Read: Self Introduction for Full Stack Developer

5. Explain the difference between an array and a linked list. When would you choose one over the other?

Answer one of this most common coding interview questions like: “Arrays and linked lists are both fundamental data structures that are used for storing the collection of elements, but there are differences in their characteristics and uses. An array is a contiguous memory block that stores elements of the same data type. On the other hand, a linked list is made of nodes, each containing an element and a reference to the next element in the list. Elements in an array are accessed using an index and provide direct and consent-time access to any element. Linked lists allow dynamic resizing since the addition or deletion of nodes can be done to relocate the entire structure.”

6. What are Binary Trees?

Binary trees in coding are used for various tasks such as implementing algorithms, organising data efficiently and solving problems. The commonly used application of binary trees in coding is implementing binary research trees. Binary research trees provide efficient searching, insertion and deletion operations.

Also Read: 40+ Data Science Interview Questions and How to Answer

7. What is a Queue?

Queues are known as linear data structures where operations are performed in the order of FIFO. In a queue, the elements added earlier are removed before those that were added later and are opposed to a stack.

8. What is the purpose of exception handling in programming? How does it help in managing errors and maintaining program stability?

Exception handling is a programming technique providing structured ways to deal with runtime errors and other exception handling that can occur during the execution of programs. With this, programmers can handle unexpected scenarios in a controlled and graceful manner, preventing the program from crashing and providing a way to recover or any other alternative behaviour.

Also Read: Self Introduction for Computer Science Student

9. Define the SOLID principles in object-oriented design.

The SOLID principles are 5 different design principles for writing maintainable and scalable software in object-oriented programming. Introduced by Robert C. Martin, these principles provide guidelines for creating flexible, understandable and maintainable codebase. In SOLID, S stands for Single Responsibility Principle (SRP), O for Open/Closed Principle (OCP), L for Liskov Substitution Principle (LSP), I for Interface Segregation Principle (ISP) and D for Dependency Inversion Principle (DIP).

10. What is Doubly Linked Lists?

Answer: A doubly linked list is a link where each node contains a reference or pointer to the next and the previous node in the sequence. Unlike singly linked lists, which only have a reference to the next node, doubly linked lists allow traversal in both forward and backward directions.

Also read – How to Crack a Personal Interview?

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