I applied online. The process took two weeks.

Jonathan and the team members whom I've interacted with at Quantexa have all been incredible—very kind and supportive. After an initial screening call, I had an informal chat with one of their senior engineers. It was a two-way conversation, asking about your background, sharing a lot of information about Quantexa, and helpfully answering any questions that you may have. There is then a short on-the-spot coding exercise. The second phase is a take-home Angular exercise with a few questions to answer that involve data manipulation. Even though I haven't had an offer, I can't fault the experience or the team.

Write an efficient function that takes yesterday's stock prices as a list and returns the best profit I could have made from one purchase and one sale of the stock yesterday.