Introduction
Hiring software engineers is a time-consuming and expensive process. How can someone know if the candidates they’re considering for their company are competent enough? Will they be a good fit for their team? The kinds of issues software developers fix are long and complex. How can you ensure you hire the right person for your team? Whiteboard coding interviews can help you in ensuring this!
Whiteboard programming interviews have become standard practice for software engineers. Several big tech companies have their versions of coding whiteboards in their interview cycles to ensure they hire the right candidate.
What is a whiteboard coding interview?
Whiteboard coding interviews are a style of interview question that assesses a potential hire’s technical and non-technical skills. The question can either be a data structure and a specific algorithm problem or a more abstract systems design and architecture-based question.
During a whiteboard programming interview, interviewers share a coding problem with candidates and ask them to outline their solutions on a whiteboard.
Why conduct whiteboard coding interviews?
Given the competition and the many job applicants, whiteboard coding interviews are a great way to screen out candidates who don’t meet hiring organizations’ criteria.
Organizations must check competency when hiring for a software developer position to establish baseline confidence. They cannot filter good candidates just from a single interview technique. However, using the right interview techniques can help you ensure certain qualifications.
Whiteboard interviews push both the interviewer and the candidate to think at a higher level. Without the crutch of development tools, syntax highlighting, or automatic error checks, the focus shifts entirely to the problem itself.
But here’s the thing — a whiteboard interview isn’t about testing whether a developer has every bit of syntax memorized. In fact, it’s the opposite. Stripping away those details creates space to zero in on the real challenge: understanding and solving the problem.
What are the different types of whiteboard coding interview questions?
Below are some of the most common types of whiteboard coding interview questions.
Algorithmic questions
These questions assess a candidate’s problem-solving abilities and quick thinking. Candidates might need to create a custom solution or apply a known algorithm to tackle a specific challenge.
Some of the examples are implementing sorting algorithms, constructing data structures, or navigating graphs.
System design questions
These questions assess a candidate’s abilities to design and implement scalable and maintainable software solutions. They may require the candidate to design a system for a certain problem or optimize an existing one.
Some of the examples are designing social media network APIs, algorithms for image processing, and components for a web application.
Language-specific questions
These questions evaluate a candidate’s expertise in specific programming languages. They can cover anything from basic language features to advanced concepts like inheritance, higher-order functions, or memory management.
Behavioral coding questions
These mix technical and behavioral skills. Candidates might need to explain how they’d tackle a real-world coding scenario, often involving teamwork.
For example, the interviewer may ask them, ‘How would they handle merging code from multiple developers with conflicting changes’?
Some of the other whiteboard programming interview questions can be of the following types:
- Debugging or code correction questions
- Puzzle or brain teaser questions
- Data structures questions
Furthermore, depending on the organization’s hiring requirements, interviewers may decide to build their own approach to these coding whiteboard interview questions.
How can organizations conduct whiteboard programming interviews?
Whiteboard programming interviews are a staple in the tech industry. They provide a unique way to evaluate a candidate’s problem-solving skills, communication, and coding proficiency.
However, these interviews can be stressful for the candidates and organizations to get right. Here’s how organizations can ensure they conduct whiteboard interviews fairly and effectively.
Start with clear objectives
The purpose of a coding whiteboard interview is not just to check if someone can write accurate code on a whiteboard. It’s to assess:
- Problem-solving approach
- Coding fundamentals
- Communication and collaboration skills
Define what you’re looking for in advance so your interview questions align with the role.
Select the right questions
Asking the right questions in a coding whiteboard interview is critical. They should be:
- Relevant to the role. A front-end developer shouldn’t have to answer for a back-end developer.
- Reasonable and not overly tricky. Pick questions that test the candidate’s skills on the job.
- Layered with a simple version of the problem. If candidates have time, they can build more on that.
Set the stage for success
Create an environment where candidates feel comfortable:
- Provide a clear problem statement: Ambiguity can be good for senior-level roles, but for entry-level candidates, clarity wins.
- Allow clarifying questions: Encourage candidates to ask questions. It shows their thought process and ability to collaborate.
- Offer tools: Use actual whiteboards, online collaborative platforms, or pen-and-paper, and let the candidates pick what suits them best.
Focus on the process, not perfection
It’s not just about the end result. Pay attention to:
- How they think: Are they methodical? Do they break the problem into parts?
- How they communicate: Do they explain their choices and ask for feedback?
- How they adapt: Do they handle hints well and improve their solution?
Remember, a messy solution with great reasoning is often more valuable than a perfect one without explanation.
Create a two-way interaction
The best interviews feel like conversations, not interrogations. Engage with the candidate during the process:
- Ask them why they made a particular decision.
- Offer subtle guidance if they get stuck.
- See how they handle feedback or alternative approaches.
This gives insight into their mindset and helps candidates feel more at ease.
Evaluate soft skills as well
Whiteboard interviews are a great opportunity to assess non-technical traits like:
- Composure under pressure: Do they stay calm or get flustered?
- Collaboration: Are they open to discussion and feedback?
- Curiosity: Do they ask thoughtful questions or suggest alternate solutions?
Provide feedback
Candidates appreciate constructive feedback. If possible, give them insights into how they performed and what they could improve on. This will reflect well on your organization and help you stand out as a thoughtful employer.
How can candidates prepare for whiteboard programming interviews?
Practice with mock interviews
The best way to prepare for a whiteboard programming interview is to practice as much as possible. Candidates should participate in mock interviews with friends, colleagues, or mentors.
This will allow them to practice their problem-solving skills and get feedback on their performance. Candidates can also find online platforms that offer mock interview sessions with experienced interviewers who can give constructive feedback.
Stay organized
Candidates must ensure that their code is organized and clean, uses clear variable names, and is well-structured. Using pseudo-code or drawing diagrams can help them stay organized during coding. They should also be mindful of their time and try to use the time allocated to reflect their skills and clarity of thought.
Communicate thought process
One key thing interviewers are looking for is how candidates approach and solve problems, work on the problem, and communicate their thought process with the interviewer.
Candidates should explain their approach and the reasoning behind it. This will help the interviewer understand their problem-solving skills and critical thinking ability. It will also help the candidates stay focused and organized as they work on the problem.
Be mindful of the time
One of the challenges of whiteboard programming interviews is time management. Candidates must keep track of the clock, set a timer, and aim to finish the interview within the stipulated duration.
They should not waste too much time on a single problem if they get stuck. Instead, they should explain their thought process to the interviewer and move on to the next question.
Start with the brute force solution
When a candidate first starts working on the problem, they should begin with a brute-force solution. This means solving the problem in the most straightforward way possible.
This gives them a baseline to work with and helps them understand the problem better. Once they have a working solution, they can optimize it for performance.
Optimize for time and space complexity
After a candidate has a working solution, they should optimize it for time and space complexity. This means reducing the amount of time and memory required to solve the problem.
Interviewers are looking for efficient solutions that can scale well. As the candidate optimizes their solution, they should explain their thought process to the interviewer.
Write clean and readable code
When writing a code, candidates should ensure it is clean, organized, and easy to understand. They should also use appropriate variable names, comments, and formatting to make codes easy to understand. This will help the interviewer follow candidates’ thought processes and better understand their solutions.
Test own solutions
After a candidate has written a code, they must test it thoroughly. They should ensure it works for different test cases, including edge cases. If they find a bug, they should fix it and test again. This will help them catch mistakes and ensure their code works as expected.
Don’t give up
If candidates get stuck on a problem, they should not give up. They should think about the problem from a different perspective or try a different approach. They should know that the interviewer is not expecting them to solve every problem perfectly. They are looking for your problem-solving skills and your ability to think critically.
Learn from mistakes
After an interview, candidates must take the time to reflect on what went well and what they could improve on. They should ask for feedback from the interviewer or someone with experience in technical interviews. They should learn from their own mistakes and use the feedback to improve their skills.
Stay calm and confident
Candidates must know how to stay calm and confident during their interviews. They should understand that the interviewer is not trying to trick or catch them. They want to see how they approach and solve problems.
So, in case of any mistakes, candidates should not panic but instead take a step back, reevaluate the problem, and try again. The more confident and calm they are, the better they will perform.
The bottom line
Though whiteboard coding interviews can be hectic, they can also be an excellent way to evaluate talent if done correctly. For organizations, it is important to design a structured, fair, and engaging process. In the end, the goal isn’t just hiring the best candidate but also ensuring they leave a positive impression of your company.
Candidates preparing for coding whiteboard interviews must understand that though whiteboard programming interviews can be challenging, they’re also a chance to show off their logical thinking and resilience.
The solution is to be methodical, stay calm, and treat the problem as a conversation rather than an exam. Practice as much as possible, understand the problem, optimize for time and space complexity, and write clean and readable code. Lastly, candidates should not give up learning from their mistakes and stay confident.
Is your organization planning its next hire? Contact us to learn how InterviewVector can help you find the right talent for your team.
