I'm in a ranty mood this evening. Looking through my past, one thing that bothers me is the ritual called "whiteboarding".
I've taken and given a lot of these interviews. I personally find the process demeaning, dehumanizing, biased, and subjective. And if the company uses the terms "cultural fit" or "calibration" when teaching you how to whiteboard, be wary.
My first software development interview was in 1996. I walked in, showed my Game Developer Magazine articles and demos (in DOS of course), spoke with the developers and my potential manager, and they made me an offer. Looking back, I was so young, inexperienced and naive at 20 years old. It was a tough gig but we shipped a cool product (Montezuma's Return). There was no whiteboard, all that mattered was the work and results.
Anyhow, my interview at Blue Shift was similar. No whiteboard, just lots of meetings.
At Ensemble (Microsoft), I got a contract gig at first. This turned into a full-time gig. The interviews there were informal and very rarely (if ever) involved problem solving on a whiteboard.
Right before Ensemble, I also interviewed at Microsoft ATG. It was a stressful, heavy duty whiteboard interview with several devs. It was intense, and that night I fell asleep at the table of an unrelated dinner with friends. I got an offer, but Ensemble's was better. I later learned it was basically a form of "Trauma Bonding". Everyone else did it, so you had to go through it too to get "in". Overall, I remember the Microsoft engineers I interviewed with seemed to be all tired and somewhat stressed out, but they were very professional and respectful.
After Age3 shipped, I interviewed at Epic. I was tired from crunching on Age3, and was unprepared. It was the most horrific interview I've ever taken or seen. Incredibly unprofessional. The devs didn't want to be interviewing anyone. I flopped this interview (and probably dodged a bullet as the working conditions there at the time seemed really bad). Nobody at Ensemble knew I interviewed there, and I'm glad I didn't leave.
Years later, I interviewed at Valve. It was another exercise in Trauma Bonding. I was so stressed it was ridiculous, and I found Dune's "The Litany Against Fear" helpful. Somehow I got through, and looking back I think Gabe Newell (who visited Ensemble and met me there) might have helped get me in without my knowledge. I was lucky to get in at all, because I interviewed as a generalist. If I had interviewed as a graphics specialist I never could have gotten in. (Because at the time the gfx coders at Valve had a pact of sorts, and unless you were Carmack it was virtually impossible to survive the whiteboard. So many graphics specialists got turned down that after a while the high-ups at Valve took notice and changed things.)
Anyhow, one of my points is, I've been pretty lucky to get to work at these places. I learned a lot. Most of the companies I worked at didn't use whiteboarding. Interestingly, the cultures of the non-whiteboarding companies were much healthier.
I sometimes wonder: if I wasn't a white male, or overweight, with all other things unchanged, would I have got these gigs? I very highly doubt it.
I've implemented and shipped tons of algorithms, products, etc. But I hate whiteboarding.
I think the tech companies use this process to slow down horizontal movement between companies. It keeps labor in place, and developer wages/prices down. The "price" of moving between companies (in terms of stress, and potential "whiteboard defeat") is purposely held high. Independent of whether or not this is done purposely, this is the end result.
If you've got to whiteboard, it can't hurt to practice like crazy. And read a few whiteboard coding interview books. Also, tap your social network and find devs who interviewed at your target company, and ask them what happened. If companies are going to do this, at least make them put some effort into it.
One trick I've seen done: After a big layoff, a group of devs gets together and starts interviewing at various companies. After every dev interviews at a particular shop, everything about the interview, and the whiteboard questions, are discreetly shared with the group. The first dev to be sent to a particular company won't be expected to get in (and very well might not want to work there in the first place). Once developers start acting as a group the entire process gets "gamed" particularly effectively.