Whiteboard interviews can be intimidating. You’re put on the spot and asked to solve a technical problem without knowing anything about it beforehand. And if that wasn’t enough, you also have to explain your solution to your interviewer.
Still, whiteboard interviews are a crucial part of the hiring process. In the video below, Farish, a developer from California, talks about how whiteboard interviews let you show that you can think critically, explain things clearly, and solve problems. These are all skills you’ll need when working with other developers. In the paragraphs below, we’ll provide 9 tips that’ll help you ace your whiteboard interviews. But first, we’ll explain what a whiteboard interview is.
Whiteboard interviews can be intimidating. As a software engineer, you know that you have the technical skills to succeed in the role But the prospect of standing in front of a whiteboard and solving complex coding problems under pressure makes even the most qualified candidates anxious.
However, with the right preparation and perspective, you can master the whiteboard interview and land your dream software engineering job. In this comprehensive guide, I’ll walk you through what to expect during a whiteboard interview, tips for success, common whiteboard problems, and alternative interview formats. Let’s break down the mystique of whiteboarding and get you ready to ace your next software engineering interview!
What Is a Whiteboard Interview?
A whiteboard interview is a screening technique used by tech companies to assess a candidate’s technical abilities, problem-solving skills and communication aptitude. During a whiteboard interview the interviewer will present you with an algorithm, data structure, or system design problem. They will provide specifications and constraints for the problem, and your task will be to solve it on a whiteboard, explaining your approach as you go.
Interviewers observe how you structure your thoughts, communicate your ideas, and analyze and code an optimal solution While syntax itself isn’t critical, your problem solving process and ability to think through complex scenarios systematically is vital Whiteboard interviews allow companies to gauge both your technical capacity and soft skills essential for the job.
Some common types of problems include:
- Algorithm challenges like sorting, searching, dynamic programming
- Data structure manipulation like stacks, queues, trees
- Object-oriented design problems
- System architecture and scalability questions
Though intimidating for candidates, whiteboard interviews allow companies to quickly assess your skills in a short time frame. Brushing up on core computer science concepts and practicing explaining your thought process is key.
Why Do Companies Use Whiteboard Interviews?
Companies rely on whiteboard interviews to screen applicants for several reasons:
-
Tests your knowledge without access to references: By taking away your computer and references, the whiteboard interview strips away any ability to look up information. The interviewer can thus truly probe your understanding.
-
Assesses communication abilities: Whiteboarding involves continuously describing your thought process. Interviewers can evaluate how clearly and effectively you communicate complex technical concepts.
-
Simulates on-the-job problem solving: Coming up with solutions on the fly, analyzing tradeoffs, and articulating your thinking mirrors real-world software challenges. Interviewers get insight into your engineering skills and instincts.
-
Allows companies to screen many candidates: Whiteboard interviews enable companies to quickly vet many applicants’ qualifications and problem solving abilities in a standardized, efficient manner.
Though whiteboard interviews have drawbacks, companies leverage them to gauge candidates’ technical foundations, critical thinking, and communication skills under pressure. Understanding why companies give whiteboard interviews can help you better prepare.
Tips for Acing the Whiteboard Interview
Conquering the whiteboard interview takes practice and perspection. Here are some tips to master the whiteboard and impress your interviewers:
-
Clarify the problem: Repeating the problem back and asking clarifying questions shows interviewers you can properly understand requirements before solving.
-
Think out loud: Verbalize your thought process so interviewers understand your strategy. Communicate each step clearly.
-
Write pseudocode first: Take time to plan your approach. Pseudocode shows your method without getting bogged down in syntax.
-
Visualize the data: Diagramming your data structures provides anchoring visuals to explain your code.
-
Don’t memorize solutions: Focus on concepts rather than canned answers. Interviewers want to see strong programming foundations.
-
Check edge cases: Consider edge cases and test inputs to identify flaws in your logic. This demonstrates analytical thinking.
-
Make time/space tradeoffs: Weigh speed vs. memory considerations in your approach. Discuss potential optimizations.
-
Admit when you’re stuck: If you get blocked, say so. Thinking aloud to work through it demonstrates persistence.
With practice whiteboarding and emphasizing clear communication, you can master the whiteboard interview. Confidence in your computer science knowledge is key.
7 Common Whiteboard Interview Questions
Let’s look at some typical whiteboard problems to expect and how to tackle them.
1. FizzBuzz
Print the numbers from 1 to 100. For multiples of 3 print “Fizz” instead of the number. For multiples of 5 print “Buzz”. For numbers that are multiples of both 3 and 5 print “FizzBuzz”.
This common interview warmup ensures you can loop through and evaluate conditions. Discuss edge cases and be careful of divide by zero errors!
2. Reverse a Linked List
Given a singly linked list, return a reversed version of that list.
Draw out the linked list visually. Discuss the need to store references to nodes as you traverse and reverse connections.
3. Binary Search
Given a sorted array, write a binary search to find if a target value exists in the array in O(logN) time.
Binary search divides the search range in half each iteration. Diagram the intervals being searched and walk through your algorithm.
4. Merge Two Sorted Lists
Given two sorted linked lists, merge them together into one sorted linked list.
Draw the two linked lists and the desired result. Walk through your algorithm visually on the whiteboard.
5. validating-parentheses
Given a string containing parentheses, write a function to validate if parentheses are balanced.
Use a stack to track open parens. If a close doesn’t match, return false. Discuss edge cases.
6. Sorting Algorithms
Write a function to sort an array of integers. Implement merge, quick or heap sort.
Pick a sort and explain why you chose it. Walk through the algorithm and visualize swaps. Handle edge cases.
7. System Design
Design a parking garage system. Allow paying for different lengths of stay.
Discuss objects like tickets, entrances and exits. Diagram the system and explain the flow. Handle edge cases like full lots.
Alternatives to Whiteboard Interviews
While widely used, whiteboard interviews have drawbacks. Some companies use alternative techniques:
-
Take home assignments – Candidates are given a real world project or feature to build on their own time with access to normal tools and references. This tests their true coding abilities.
-
Live coding platforms – Interviewers can observe candidates coding in real time on sites like CoderPad that provide code editors and allow collaborating.
-
Technical & culture interviews – Some companies rely more on conversational interviews focused on technical background, problem solving approach, and cultural fit rather than whiteboard challenges.
-
Portfolio reviews – Evaluating a candidate’s code samples and past projects can demonstrate their abilities without whiteboard puzzles.
With technical skills, communication practice, and the right mindset, you can tackle whiteboard interviews with confidence. Brush up on core data structures and algorithms so you have strong foundations to draw from. Stay calm, think aloud, and visualize your approach. While whiteboarding poses challenges for candidates, preparation and poise can help you master this common interview format.
Don’t get flustered if you forget an element of syntax
If you can’t remember how to write a command exactly, it’s better to admit that and put a symbol or other note in its place. This shows that you understand what the code can do and how it fits into your solution. In this way, your knowledge of logic and problem-solving can still shine through.
Define your inputs, outputs, and edge cases
After you’ve clarified the problem, it’s time to start finding a solution. Outputs are what you expect the inputs or functions to do. Write them down and explain how they will work. Edge cases are rare or unexpected inputs that could cause your functions to fail. You should fix them as you find them.
In the video above, Farish shares an example. Imagine that your task involved merging two sorted arrays to a new sorted output array. In this case, your edge cases would be duplicate numbers in the two input arrays.
Whiteboard Coding Interviews: 6 Steps to Solve Any Problem
FAQ
What are whiteboard interview questions?
What is the white board session in an interview?
How long is a whiteboard interview?
