How to prepare for a coding interview

The software development industry has gotten more competitive with each day. As a result, developers now have to stay up-to-date about rapidly evolving technologies while staying in touch with the fundamentals. So it makes sense that preparing for a software developer interview has become a daunting task in such an era. After all, with so many different criteria and resources to learn from, it can get overwhelming.

However, we can smartly prepare for the coding interview process once we have broken it down and see how recruiters prepare coding interviews. Then, once we know what and how to practice, we can choose the best resource that helps us practice and improve.

In this article, we will present a step-by-step methodology for preparing for a coding interview. I will show what aspects to focus on when preparing, how to prepare for the technical and behavioral interviews, and which resources to use to prepare adequately.

Get familiar with the evaluation criteria at tech companies

To prepare well for a coding interview and increase the chances of acing it, we need to know what its process looks like. Specifically, we need to look at how companies prepare coding interviews and how it changes from company to company. Once we are clear about the evaluation criteria of companies, we can smartly strategize our preparation.

While the strictness of criteria can differ based on the seniority of the role, here are some common points interviewers assess candidates over:

  • Correct implementation and results: When given a coding problem to solve or an algorithm to implement, the correctness of the solution matters a lot. Hence, we should have ample practice to be confident about our solutions. Code solutions that are correct and exhibit good software practices are what the interviewers look for.
  • The rationale behind the solution: Apart from giving a neatly written and constructed solution that gives correct results, we must also impress interviewers with how we explain our approach. Since software development is deeply collaborative by nature, we have to devise efficient approaches and prove we can communicate them effectively.
  • Code style and conventions: Following best practices in terms of coding style and conventions are important. Companies look for this skill since many developers create efficient but hardly scalable solutions. Similarly, many developers cannot create elegant solutions that can be maintained and contributed to by others. Hence, we must learn effective coding style practices, like modularity, scalability, etc., and regularly practice them. 
  • Testing: Many coding interview processes take a different approach with their assessments. They see if candidates can adequately test poor solutions and improve them iteratively. Hence, we must consider edge cases when devising coding algorithms and ensure they handle most of the cases. We must also learn how to test a solution against failure cases to improve it iteratively.
  • How we submit the solution: Once we have devised our solution, tested it for edge cases and correctness, and ensured it follows the best coding conventions, we must submit the solution appropriately. It is our job to ensure that anyone reading the code understands what each part does. For example, we must adequately add explanations as comments under functions or complex pieces of code. 

    The solution must also be packaged appropriately, with all necessary dependencies and requirements. This could be in the form of a zip file containing a text file with instructions for building and running the application. Or it could be a Dockerfile to build a container and run the application within it.

Such evaluation criteria help companies ensure that they select the best talent for the position. Since we want our talent to be recognized, we should prepare coding interview practice plans, so we can tick all boxes and gain the opportunity we aim for.

Research the company and how you will be evaluated

Companies prepare coding interviews, which are a mix of standard evaluation criteria and specialized assessments. Recruiters and interviewers use both to first test a candidate's foundational skills and knowledge, and then their abilities within their area of focus. We talked about the general evaluation criteria in the previous section, but we also have to look at the company-specific criteria.

We must research what the company is looking for and how its internal processes work. Specifically, we need to know what technology stack they use and what are their preferred software development processes. The job description for the role describes all such information, and it is important to read through it and plan our preparation accordingly.

Prepare for the technical interview

The technical interview is the most important part of the coding interview process. Hence, we need to prepare extensively and thoroughly for it. However, most developers find it challenging to organize their preparation approach and follow through successfully. But since the technical interview will decide the outcome of the coding interview process, we must prepare smartly.    

Here are some steps on how to prepare for the technical interview:

Create a study and prep plan

A major obstacle for developers preparing for coding interviews is the number of topics and concepts they must cover and practice. After all, we can expect a question from any level in a technical interview. Even the more advanced questions or tricky challenges are designed, so interviewers can simultaneously assess the developer for strong foundations.

Hence, we must take a systematic approach with our technical interview preparation to ensure we cover all important information. A smart way to do so is to create a coding interview prep plan. Such a plan would take the knowledge we have to cover and spread it across the time we have for preparation. Such a plan also helps create small goals for us to achieve and build our self-confidence.

There are multiple approaches we can take when preparing our plan:

  1. 1
    We can learn or revise each topic in a category and practice a mix of coding challenges from the category.
  2. 2
    We can take each topic, learn it, and practice it in depth until we feel confident about it, and then move on to the next topic.
  3. 3
    We can combine both approaches where we learn each topic in a category and practice it until we are confident. Then, we can practice various challenges for all topics in a category.

Here is a sample coding interview prep plan that gives an idea of how we can plan our technical interview preparation and which we can practice as needed

Practicing coding interview questions

The coding problems can also start from more straightforward ones to more challenging ones. Set time constraints to know when to give up and look up the answer. However, we must consider giving up a learning opportunity, not a defeat. After all, the study plan is there, so we can make our mistakes prior and avoid them in the interview.

Some popular and important coding interview questions to practice are (ordered in increasing difficulty):

  • Find the middle of a linked list
  • Find the diameter of a binary tree
  • Clone a given graph
  • Validate Binary Search Tree

  • Find the longest palindromic substring

  • Serialize and then deserialize a binary tree

Choose a programming language

We must choose and settle on a certain programming language for our technical interview. All the algorithms and examples we will give will be in this language, and it will showcase our proficiency with it. Hence, we should pick one that we are comfortable with and know fairly well.

Recruiters can ask about the performance of our preferred language in interviews. It is helpful to have a basic understanding of the language and how it works underneath. Remember that learning an entirely new language is not a good idea since it can take a while to get comfortable with it, and it can cause us to lose confidence in an interview setting.

Build a programming mindset

Apart from learning conceptual knowledge and practicing coding problems, we must build solid algorithmic problem-solving and analytical skills. After all, while the solution to challenges can be straightforward, designing an efficient algorithm to reach there isn't always as easy. Hence, we should practice more questions that strengthen our algorithmic problem-solving.

Interviewers don't just want to see what we know and have practiced. They also want to assess if we have the right mindset to grow in the role we are applying for. Hence, we must show that we have a 'developer mindset.' Such a mindset is built on the following elements:

  • Learn to focus on challenges and view them from different angles until you reach a solution.
  • Learn to love the process and create curiosity within yourself that drives your motivation to work on challenges.
  • Remember your bigger goals and why you are in a role in the first place.

    Remember to reach out for help whenever needed and embrace the collaborative nature of software development.

    Keep looking for initiatives to start and new things to learn. 

Focus on the pillars of the coding interviews

When preparing for the technical interview, we must focus on the crucial aspects that interviewers assess for the said role. It requires research into the role's requirements, the company's work, technology stack, and technological infrastructure. Then, we can focus on preparing and practicing those aspects the most.

For example, suppose the coding interview process is for a Quality Assurance engineer. Then, the technical interview will focus on assessing programming skills, experience with web development, and knowledge of testing frameworks and libraries. Hence, we must prepare a study plan to revise and practice these topics amply.

Practice as you learn by solving coding problems

A strong mastery of concepts might be important to ace technical interviews, but lacking practice in solving coding interview questions definitely damages our chances of success. Hence, we must keep practicing coding problems and making mistakes to learn our lessons. We should specially practice questions related to topics and concepts we have shortlisted as important for the interview. 

Amazing real-world tech challenges as never seen before

Most technical tests kind of suck. That's why we build our own code challenges that companies are taking for their candidates' assessment.

Each challenge you solve is reviewed by our Tech Mentors, who generate a technical skill report and give you detailed feedback based on your performance.

Prepare for the behavioral interview

Another important part of every coding interview process is the behavioral interview. After all, we as software developers don't just work on technical challenges by ourselves. We also collaborate with other developers on projects and have to communicate efficiently with colleagues. Hence, every company prefers that its software developers have strong people skills along with technical abilities.

Here are some important ways to prepare and ace behavioral interviews:

Evaluate your soft and hard skills

A common challenge with behavioral interviews is that interviewees get overwhelmed by what skills they should highlight. Many often forget to bring up crucial skill sets whose mention would have benefited them. 

Hence, we must list all the important skills and technologies we have experience with. With all such information in one place, preparing an introduction and descriptions of previous work becomes much easier.

Prepare a good introduction and interview questions

 Interviewers assess the communication skills of the interviewee in such interviews. Hence, we should prepare a brief yet thorough self-introduction. It should describe our academic and professional backgrounds, career aspirations, and hobbies. 

Once we are confident about our introduction, we should practice its delivery, since the actual moment in the interview can be nerve-wracking. At the same time, we should also practice answering other common behavioral interview questions found in mock interviews.  

Practice describing your work

Behavioral interviews also dive into your projects and previous professional experience. While describing such information, we must ensure we come forth as professional and confident. 

For example, when describing previous professional experiences, we should focus on what lessons we learned and what skills we gained. Similarly, we should practice explaining information concisely when explaining projects and technical interests. Specifically, we must highlight the effort we put into the projects and how we overcame challenges. 

Be prepared for the salary and offer negotiation

Since the behavioral interview is often the last step in the coding interview process, it can precede the salary offer. Many companies directly present an offer at the end of the interview. Hence, we must also practice our ability to negotiate the salary offer as part of our preparation.

 Before the interview, we should research the role and its associated compensation at the company. Then, we must practice the scenario we are offered the figure and how we will navigate it. It is important to be professional in the negotiation while establishing what we suggest is a fair ask. 

Build self-confidence

We must improve our confidence level since it is a point of focus for behavioral interviews. After all, a lack of confidence can overshadow our experience and skill set. Hence, we must build self-confidence while talking about our achievements and abilities. 

One way of boosting our self-confidence for the interview is through mindfulness and positive self-talk. We must believe in our abilities and tell ourselves we are capable and deserving of the role. 

In the worst-case scenario that the interview doesn't fare well, we must remind ourselves that it doesn't imply anything about our abilities. The behavioral interview can be an opportunity to make mistakes and learn important lessons that will help us with future interviews.

Recommended resources to get started

We now know how we can plan our preparation for a coding interview and what it will involve. However, it is important we choose the right resource to practice and study for our coding interview prep plan. While most coding interview preparation platforms feel similar, each has its own set of advantages and disadvantages.

Here are some resources I have gathered to help you get started with your coding interview preparation:

  • Rviewer: It is one of the most popular code assessment platforms where developers can come to practice coding problems and get crucial feedback from senior mentors working in the industry. Developers can also find jobs that fit their profile and prepare for coding interviews.
  • HackerRank: It is a platform with hundreds of coding challenges to help you practice and improve your skills. It offers explanations and gives users badges once they perform excellently in coding competitions.
  • W3Schools: It features many articles and crash courses that help you quickly revise conceptual topics. The platform also has built-in coding examples to help you revise programming syntax for popular languages.

Wrapping up and next steps

Preparing for a software developer interview can feel intimidating. However, following a step-by-step approach and creating coding interview strategies can make it more manageable. By setting smaller goals for ourselves, we can revise important knowledge, practice and improve our skills, and ace all coding interviews we want to give. In the process, we can boost our self-confidence and increase our chances of success.

The next article will show the best strategies to adopt when approaching and solving coding interview problems. It will also explain how to practice to increase your chances of solving all coding challenges.