Top Tips for Coding and Programming Interview Preparation

The competition during coding interviews is nothing short of cutting edge. Proper coding interview preparation is crucial to clear any top-tier company interview. This article discusses some tips, questions, and resources to help you ace your coding interview.

If you are preparing for a tech interview, check out our technical interview checklist, interview questions page, and salary negotiation e-book to get interview-ready! Also, read Amazon Coding Interview Questions, Facebook Coding Interview Questions to Nail Your Next Interview, and Google Coding Interview Questions for specific insights and guidance on Coding interview preparation.

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In this article, we’ll cover some tips to help you with your coding or programming interview prep:

• 1. Know the Coding Interview Process
• 2. Read Books on Coding Interview Preparation
• 3. Prepare for Whiteboard Coding Interview
• 4. Practice on Coding Platforms for Coding Interview Preparation
• 5. Prepare for Common Follow-Up Interview Questions
• Bonus Tips for Coding Interview Preparation
• FAQs on Coding Interviews

1. Know the Coding Interview Process

Coding interviews are about how you think, adapt, and communicate just as much as they are about how much you know and how well you can solve a problem. A typical whiteboard coding interview process involves:

• Interviewer and candidate exchanging niceties 
• Interviewer describing the problem statement
• Candidate asking clarifying questions
• Candidate validating assumptions
• A brief pause during the interview as the candidate thinks of an optimal solution
• Candidate thinking about the solving process out loud
• Candidate explaining trade-offs
• Interviewer asking follow-up questions and the candidate answering them
• Writing a complete solution that compiles
• Interviewer and candidate discussing the solution like one would discuss with team members

Recommended Reading:
Amazon Interview Process Guide
Apple Interview Process Guide2. Read Books on Coding Interview Preparation

There’s a lot you can learn from books that’ll give you an edge during your coding interview. Some of the top-rated books for coding interview preparation are:

• Cracking the Coding Interview: 189 Programming Questions and Solutions by Gayle Laakmann McDowell
• Elements of Programming Interviews in Python: The Insiders' Guide by Adnan Aziz, Tsung-Hsien Lee, et al.
• Elements of Programming Interviews in Java: The Insiders' Guide by Adnan Aziz, Tsung-Hsien Lee, et al.
• Elements of Programming Interviews: The Insiders' Guide by Adnan Aziz, Tsung-Hsien Lee, et al.
• System Design Interview – An insider's guide, Second Edition by Alex Xu
• Coding Interview Questions by Narasimha Karumanchi
• A Common-Sense Guide to Data Structures and Algorithms, Second Edition: Level Up Your Core Programming Skills by Jay Wengrow

Recommended Reading: Coding Interview Cheat Sheet 

3. Prepare for Whiteboard Coding Interview

Taking mock interviews, solving problems, and explaining during mocks as you would during your coding interview will help you be comfortable during your interview. You can join an online mock interview course or take the help of a friend for this process. 

Here are some steps you can take during your mock interviews as well as on your interview day to perform your best:

1. Know your syntax. While it may not be the most important thing, forgetting syntax can cost you your flow and confidence, which is essential to pull you through.
2. Validate assumptions. Solving the question based on unverified assumptions can likely lead you to an invalid solution. It’s always better to ask if it’s okay to make any assumption you’re making, even if small.
3. Understand constraints. Space and time resource constraints you need to abide by, along with constraints on valid input types and sizes, are important things to consider when coming up with a solution.
4. Take a pause. Impulsively solving a question only to realize it’s not the most optimal solution later is unwise. Pausing to think of an optimal solution can save time and improve your chances of success. Meditation and mindfulness can help you achieve this ability.
5. Communicate your thought process. Interviewers need to know how you think. They can guide you or give you hints, or ask you relevant questions as you think aloud, which may help you get to the most optimal solution faster. Talking out loud to a friend similarly during a mock interview can replicate that dynamic for you.
6. Decide a data structure and algorithm appropriate for the question given resource constraints, and implement a solution that compiles. There’s no need to first focus on fixing minor details if your solution isn’t ready. You can come back to it later.
7. Explain your solution. Explain any trade-offs, and answer any questions as you would with a team member.

Recommended Reading: Cracking the Coding Interview: 9 Extremely Important Things You Should Know

4. Practice on Coding Platforms for Coding Interview Preparation

Coding challenges can help you get interview-ready. Here are some of the best coding websites to help you sharpen your competitive side for your interview preparation:

• TopCoder
• Codility
• Project Euler
• HackerRank
• Coderbyte
• CodeChef
• LeetCode
• Codeforces
• Codewars

5. Prepare for Common Follow-Up Interview Questions

While preparing for coding interviews, practicing coding problems takes center stage. But you must also be ready for some of the follow-up, concept-based questions that interviewers ask. Here are some common follow-up questions that can be asked when coding in your preferred language:

C++ Interview Questions

• Describe the OOP and SOLID principles.
• Is it possible to have a recursive inline function?
• Can the C++ compiler ignore inlining?
• Tell me more about ‘this’ pointer.
• What’s the use of the Friend function and class?
• Differentiate between function overloading and operator overloading.
• Can we compile a C++ program without the main() function?
• Is it possible for us to overload a destructor?
• Differentiate between struct and class.

Python Interview Questions

• How will you easily check whether all the characters in a given string are alphanumeric or not?
• Differentiate between pickling and unpickling?
• Differentiate between deep and shallow copies.
• What are some tools in python for identifying bugs and performing the static analysis?
• What is the ‘main’ function in python, and how would you use it?
• Differentiate between a package and a module in python.
• Talk about Pandas and how you can combine data frames in it.
• How would you access the first five and last five entries of a data frame?
• How would you remove duplicate elements from a list?

Java Interview Questions

• Tell me a bit about the Java Virtual Machine.
• Differentiate between JRE, JDK, and JVM.
• What are all the types of memory areas that JVM allocates?
• What’s responsible for Java’s 'write once and run anywhere' characteristic?
• Is Empty .java file name considered a valid source file name in Java?
• Are one or more of these keywords in Java: delete, exit, next, main, null?
• Name all the access specifiers in Java.
• What components does one get in the Java download file, and what is the difference between them?
• Explain Object Cloning.
• Why is Java not considered completely object-oriented?
• Define Wrapper and Singleton Classes in Java.
• Explain the ‘this’ and ‘super’ keywords in Java.
• Define Late Binding.
• Describe the lifecycle of a thread.

Bonus Tips for Coding Interview Preparation

• Breathe, and slow down your pace to think and communicate more clearly.
• Don’t immediately start solving. Take a pause after understanding the question.
• When you have forgotten something or don’t know, saying you don’t know is preferable to acting as if you do, as that wastes time, isn’t productive, and looks terrible.
• Discuss your solutions as you would with colleagues in your team.
• If you’re having a blackout, drawing the solution pictorially, going through a brute force solution first, solving a small part of the problem, or solving a simpler version of the problem first would help you get out of the rut. Communicating out loud can help you get unstuck as well.
• Listen well and allow the interviewer some space to speak. You’ll get more information to work with that way.
• Talk out loud as you evaluate space and time constraints.
• Complete a working solution first instead of trying to perfect things you don’t have to.
• If you forget the syntax, use an English phrase and say you’ll get back to it later. This will not break your flow of noting down the solution and give your brain time to remember the syntax.
• If you need to implement a small part, you’re not quite sure how to implement it just yet; instead of abandoning your solution to solve that part, call a helper function, finish the rest of the solution, then implement the helper function as well.
• Leave space for clarity, adding notes, and correction when writing. Start from the top of the board, so you have enough space.
• Explicitly mark positions you need to come back to for checking or changing something. It is essential not to break the flow while noting down your solutions and thoughts too much.
• Use variable names that describe what they store and function names that describe what they do.
• Test for all possible edge cases and many small errors that may be present.

FAQs on Coding Interviews

Question: What are some key Data Structures and Algorithms to learn when preparing for a coding interview?

Arrays, strings, maps, linked lists, queues, graphs, and associated algorithms are crucial to clear a coding interview in any tier-1 company. Start solving some easy problems first. If you can’t solve some easy and medium problems first, it may be unwise to target difficult problems directly. Read Best Way to Learn Data Structures and Algorithms for more tips.

Question: How to start preparing for coding interviews?

You can start by visiting your target company’s website, careers page, and the specific job posting you applied for to see what they’re looking for. 

You can then learn skills that make you a better fit for the job and figure out how you can be best aligned with their vision, values, and their company goals. Practice problems that vary in type but belong to the difficulty range your target company desires and tests for.

You may also want to look at your target company’s competitors and competing offers to better understand the job market and requirements.

Recommended Reading: How to Crack a Coding Interview With 2 Months of Prep

Question: What is the best website to prepare for coding interviews?

While there are many coding interview preparation sites, you should use one (or a few) that best fit your needs. Building on your strengths and focusing on your weaknesses together is key. At Interview Kickstart, we provide several pathways designed to set you up for success. Check our website for more information.

Ready to Nail Your Next Coding Interview?

Whether you’re a Coding Engineer gunning for Software Developer or Software Engineer roles, a Tech Lead, or you’re targeting management positions at top companies, IK offers courses specifically designed for your needs to help you with your technical interview preparation!

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