They have a big, open funnel and put everyone through it, clearly using the series of seven 1-hour interviews to grind down the volume of applicants to a manageable number.

Setting up the interviews was simple email responses. The coding interviews themselves were not nightmarish LeetCode/HackerRank puzzles, but a non-trivial base puzzle with two possible "level-up" extensions. There was one person presenting the puzzle and evaluating your progress, which I sense was done by ticking items off on a checklist: "applicant did this," "said that," "did not do the other." Time will be your critical restraint.

Feedback at each successful phase was next day, but took ten days and considerable prodding when I failed.

Capture the current price of a commodity from a tickertape stream of out-of-time-order updates.

What is the current price, the maximum price ever, and now please delete a price.