The Best Whiteboard Interview Advice

Communicate!

The best piece of technical interview advice I have received and can impart upon you is to communicate, communicate, communicate! This may seem like an anti-climactic piece of advice, but I hope to be able to demonstrate to you that it’s actually the most important skill to prepare prior to an interview.

Restate the Question

_Do you understand what they’re asking you to do? Prove it. Restate the question for them and seek affirmation. You might actually be surprised to find you don’t fully understand what they’re asking for — perhaps the question is similar, but not the same, as a practice problem you have completed in the past. _

Ask About Edge Cases

It’s still not time to dive right into coding the solution. Think for a bit about the inputs and expected output and think about potential edge cases to the problem. Ask about them. In many cases, the interviewer hasn’t even thought about edge cases and will make something up. That’s great — it shows you’re analytical and will work hard to try to prevent bugs (which often crop up due to edge cases).

Ask About Test Cases

This is free and you should take advantage of it. Simply ask if there are any test cases that the function should pass. Your interviewer might be expecting you to ask this question, so it might be necessary. But it’s also possible the interviewer was not expecting the question and will think “ah, this candidate knows about testing!”

Write Pseudocode and Ask If It Makes Sense

Again, you don’t actually want to start writing code in an actual language. You’ll find yourself constrained by trying to remember the methods or other idiosyncrasies of the language rather than trying to come up with the correct logic. Instead, let your interviewer know you’re going to start by writing pseudocode and fill in the actual code later. (Coincidentally, this is a reasonable way to write actual code as well).

Write the Actual Code and Ask if it Looks Good

You should now convert your pseudocode into actual code. You don’t even need to remove the comments. At this point, you just need to plug the appropriate code for your language in. If you forget some syntax or a method name, you should be able to ask your interviewer for this information without too much grief. If they give you trouble, just say you’ll leave it as pseudocode for now.

Stuck? Ask for Help!

If you’re having trouble along the way, it’s not illegal to ask for some help. Just phrase it conversationally.