Followed employee referral.

First, I did a technical phone screen with the hiring manager. This consisted of a discussion of background, potential work once in the position, and a scheduling optimization question.

I was brought in to interview with two groups. This was done over three-quarters of a day in a series of two-person team sessions, with a break for lunch with the managers from both groups.

Questions included fundamental computer science, including networking, algorithm design, and threading and race condition prevention, in addition to optimal scheduling through experiment.

I discovered afterwards that this question just appeared in the Huffington Post article, "15 Ridiculously Hard Job Interview Questions From Top Employers Like Google, Goldman Sachs."

Out of 25 horses, pick the fastest 3 horses.

In each race, only 5 horses can run at the same time.

What is the minimum number of races required?