Data structures and algorithms I actually used while working at tech companies

Ideally the interviewer shouldn't be concerned about absolute code correctness, such as syntax or argument position, and should be interested more in how you're able to solve the problem, which should be a novel, yet simple task that doesn't require studying up on 200 level algorithms.

You want to hire developers (for permanent full time roles, at least) who have a good conceptual grasp of programming and logic, rather than their particular knowledge of a language or framework, or their ability to search on stackoverflow and run their code through a linter.

The worst interview problem I've been given was to write an AngularJS directive, I think literally to simply take an attribute and display it. I can't remember at the best of times the syntactical oddities of AngularJS, let alone when writing with pen and paper in an interview with no resources.

One of the better problems I was given was around parsing XML, from memory validating that opening tags matched closing tags, while allowing for self-closing tagsI remember the problem specifically didn't include any more complex facets of XML. Another was to reverse a string in-place ("hello world" -> "dlrow olleh"), and then to modify the algorithm to reverse the words but keep them in place ("hello world" -> "olleh dlrow"). Obviously in the real world you'd just use built in methods, but it's a problem that should be solvable without digging up your old lecture notes.

I've always felt comfortable writing code (or at least psuedocode) with a pen, but I think it's unfair to require a candidate to solve the problem on paper or whiteboard if they feel more comfortable typing on a computer instead, all that achieves is disadvantaging otherwise capable candidates who for one reason or another can't write code with a pen and paper. As long as they aren't googling "how to reverse a string in place", it immaterial what writing tool they use. If they feel more comfortable using a brush and papyrus, or carving a runestone, then that should be perfectly acceptable too (provided they bring their own writing material).

Is that something they’re going to do on the job? Very unlikely. So why are you not only testing for it but testing for it in a fake time-pressured stressful situation that also rarely exists on the job? (Yes , we all have deadlines but when are they ever 15 minutes on the spot?)

Perhaps you should have entered the education field where you could give such exams day after day to your heart’s content?

> Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so fuck off.

First, it's not remotely true that 90% of Google engineers use Homebrew, seeing as how almost all development is done on Linux (Max Howell is unjustifiably full of himself here). And secondly, he doesn't know why he wasn't hired, but it may well be because of the entitled attitude on display here rather than any coding shortcomings. No one wants to work with pompous rockstars. They may be fine for developing one-person projects out in the wild but they don't work well on team projects at large companies.

If you go into an interview with the attitude that the problems you're being asked to solve are beneath you and that you just flat-out deserve the job without having to prove yourself, your success rate is gonna be poor. To a big corporation, almost no one is as big of a deal as they might think they are, unless they hold a Turing Award or similar.

I did it once or twice when I was 8 years old and didn’t have a computer yet :)