Ha, I read your comment first and thought you were somehow overreacting, but then I read the piece and I agree with you. The author doesn’t seem to realize that the flavor of interview he’s running is deeply trainable, and that one can become very, very good at tic-tac-toe style questions after a year or two of intense study. But who would do that? Well, a whole lot of IOI/ICPC contestants did. So, he’s mostly just hiring for people who joined the same club as, I assume, himself.
It's funny. The older I've gotten, the more code I've written, and the slower I am to write code.
When I was fresh out of college the 'obvious' approach just appeared, and I was off to write it.
Now, any problem I am slow to peel apart in my mind, decide what the best way to approach it is, based on the language I'm using, what I'm feeling right now, readability, maintainability, etc.
Tic Tac Toe? Interesting; should I store board state as a 2d array, or a single array? The obvious approach would be to try and play every possible game with backtracking, but perhaps instead it would be simpler to just generate every possible permutation of 5 Xs and 4 Os? Would that work; on the one hand a badly playing O might lose after just 3 Xs, but we could still fill out the board if we 'kept playing', so it maps one to one, so maybe! Of course, then you risk situations where both X and O wins, so maybe not? Also, what about rotations; we could reduce our work by ensuring we didn't try to solve for cases that are just rotations of one another, but is the book keeping of that more work than just brute forcing it, given the constrained nature of the problem? Etc etc.
Writing working code matters, yes. But if you're looking for people who think just a few seconds before typing anything, and then seem frustrated they can't type fast enough, you're optimizing for juniors.
Which is touched on; you don't need to evaluate game states, you merely need to count them. A game that ended with X or O before the board filled out could still have additional Xs and Os written on it; while that would "lose" the winning state, it's immaterial since you aren't interested in the state, just the outcomes (or, possibly, the ways to get there).
I wasn't actually asking or pondering over it (the answer would in part be determined by what is meant by a "valid game"); I was just presenting a train of thought akin to what I would have in such a situation, examining the question in various lights as to ways to solve it, and generating clarifying questions to ask or ideas to explore.
IOI contestants (and people that can memorize lots of difficult algorithms) tend to have high intelligence. If you're looking to hire really smart people and you don't care about false negatives, it's a good way to approach the problem.
The entire point is to hire people that 1) are interested in exploring algorithms on their own time (i.e. they're interested in more than just getting paid for a job, they're interested in interesting problems too) 2) are competitive and want to win 3) are hard working and intelligent (i.e. they had to study for these competitions and do well in them).
You might miss a lot of smart people but it's pretty likely if you ask really hard algorithm questions that you'll filter out any not smart people. If you're reacting badly to this style of interview, that's because you're not their target talent pool.
Actually I’m a fan of algorithms questions! Of course, getting an engineering staff full of IOI medalists is a wonderful situation and will attract more talent. But I and others here are recognizing the role played by practice and grinding on this specific flavor of problem. The author states that intelligence is unchangeable and divides candidates into talent bands - but actually, his test is significantly impacted by factors other than intelligence. His framing is just weird, to be honest. “People who think faster than they can type” isn’t really a meaningful category, yet he’s turned it into a theology of interviewing.
> So, he’s mostly just hiring for people who joined the same club as, I assume, himself.
Not so. From the article:
> First, I cannot myself pass this interview. Last time I tried, I got the correct answer after about forty minutes or so. I could get it down with practice, but it doesn't matter-- I think slower than I type. That's a no hire. The point of the interview is to hire extremely talented engineers, not engineers as talented as me.
I think this is mostly a sign that he’s out of practice - he’s a former PhD student working on database tech, the man has spent plenty of time writing algorithms. I’m claiming that he’s under weighting the effects of practice on how well (specifically, how fast) candidates perform here. When people are coding at typing speed, it usually means they’re not really thinking at all - rather recalling a similar template from memory.
He even says "I could get it down with practice", it's quite astounding that he doesn't get the importance of preparing for this specific type of test. I've been doing competitive programming in highschool, was decently good at it (got to IOI, got some medals). First year in uni they wouldn't allow us to compete in ACM, by the second year I felt like I was competing with my hands tied due to the lack of practice. One year of pause is all it took.
There's _some_ truth in some things that he says though, even though HN doesn't appreciate it. Like, anecdotally, I have a friend who refused a Google offer (when Google was much smaller but still a big-ish name) and went for a startup because the interview problems at the startup were very difficult and he thought they were going to have interesting problems to solve. I took note of that and made sure my interviews were as difficult as the candidate could take it - like, go progressively harder until the candidate is stuck, then back off. This works fairly well especially with just-out-of-university hires, there's a certain type of people that notice it and like being challenged. And they're often very good employees. (of course, what the author suggests in the article is WAY over the top, I'd agree his process is broken).
