Slack interview questions

TLDR; Slack's interview process was one of the best I have experienced in 10+ years. My total time in the interview loop was about 7 weeks. I was referred to them through a network contact so my experience may be different but it was: -Phone call with a recruiter - focused on my experience and culture fit -Phone call with an engineering manager - technical dive into my work history, challenging projects, etc -Coding exercise - Review code for a project that was completed by a mid level-ish individual -Full "virtual interview" - 3 and a half hours of meetings with various folks at Slack. Mostly focused on coding, team/culture fit, and systems design. -Team match interview - I met with three teams which had openings for my skill set. Each team was awesome but one in particular was more aligned with my goals. The recruiter that I worked with was extremely helpful and transparent throughout the process. They gave me info on what to expect for each step and how to prepare for them as well. It was as if the recruiter actually wanted me to succeed! What a concept!

Onsight getting to know you and your background. 2nd interview was a whiteboard session where they share a challenging org design issue. They lay out a scenario where you need 2x the headcount to support but you don't have it. What do you do?