The unoptimized code was a Python problem I believe (it was a while ago so not sure on the language), but you don't really need to know any Python, they will walk you through it and any syntax you don't know. Just find any issues, verbalize your thoughts and fix them even if they are minor. For the whiteboard problem, be ready to explain your solution and iterate over it with some curveballs thrown in. The question is vague enough that you can approach it from multiple angles, I went with Java syntax and used hashmaps to store my information. For the take home assignment, it was a mobile assignment in my case. Take your time to understand the API well and think about how you want to display the information it fetches.