The typical interview process includes:

• 30 min online quiz
• Recruiter call
• Recruiter interview
• Engineer interview
• 6 hour coding test
• 15 min presentation about coding test
• 1 on 1 interviews

The 6-hour C++ coding challenge isn't challenging in the technical sense. The coding test tries to challenge your ability to either:

1. Imagine what they could throw at you and do your due diligence to come prepared.
2. Type really, really fast and know how to implement data structures.
3. Know knowledge about the challenge ahead of time by knowing someone who interviewed before, knowing an employee, or by reading this review (which kind of falls into #1).
4. Work well in the trade-off space of non-functional vs. functional requirements; product owner type skills for those of you familiar with Scrum.

If you are reading this review, you already have a leg up on other candidates who haven't. My advice is to implement a library of common data structures before the interview. It has to be your own work, and you will need them. If I had this advice before my interview, I would have finished it in 1.5 to 2 hours.

I don't think this coding challenge tests what it was intended for very well, which is why I am revealing this information to you. I have encountered the same technical problem from other interviews, and it was administered much better with an in-person design session and a reasonable coding portion. My hope is to level the playing field and give feedback to improve SpaceX's interview process.

I think the test was intended to set a high bar and to see if you could code under stress. I believe that's easily overcome by reading this review, and it doesn't test what it should test: communication skills (verbal and non-verbal), how you approach problems, can you code, can you design, can you work well with others, what knowledge do you have about data structures, or are you just looking them up and coding them.

Either way, the 6-hour test does reveal something about the company and the people who work there. I would have loved to have reached the one-on-one interviews or the presentation stage to see what SpaceX is all about. Unfortunately, I am left with a less-than-satisfying impression of the company.

Nothing was technically difficult. It was just the odd situation you are placed in.