Mixpanel Machine Learning Engineer interview questions

First I was asked to complete a timed online challenge. There're roughly 50 questions covering various coding languages and software engineer knowledge. I quickly realized that no one could answer all the questions correctly so I just relaxed and did my best. One week later they told me that they'll continue on to the phone interview. Soon after that I attended the afternoon onsite interview. Note during onsite they're actually using the same collaborate website as phone interview, meaning you'll be coding on an (old) Macbook instead of whiteboard. I didn't get an offer in the end, but the people I met are very nice and they helped accelerate the process due to my schedule.