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I was also a fan of this tweet until I found out what inverting a binary tree actually is. Being asked to code relatively complicated algorithms like balancing

I was also a fan of this tweet until I found out what inverting a binary tree actually is. Being asked to code relatively complicated algorithms like balancing a binary tree is one thing, but this guy essentially failed FizzBuzz. At that point it’s not about testing the limits of your candidate but filtering out the low hanging fruit. Obviously I don’t have the whole story of the interview, but it makes me a little worried for homebrew.

SQueeeeeL 5y ago
Inverting a binary tree is essentially trivia in the context of most programming, honestly, if I had to do it without a library I'd be extremely worried I'd fuck it up in some subtle way. Max Howell obviously has a strong understanding of file systems, web protocols, package management, and a whole other suite of skills I'm too stupid to understand.
pydry 5y ago
The fact it was trivia irrelevant to most programmers is precisely why it was such a brain dead question. Asking what FizzBuzz is is similarly useless and would also make an abysmal question.
ClumsyPilot 5y ago
"until I found out what inverting a binary tree actually is" So do you consider youself a terrible, unhire-able developer? Presumable your still has quadrupled since you found out this information?
- vultour 5y ago
  No, but I assume that the inteviewer will elaborate if you ask them what they mean. I don't consider people who don't know what FizzBuzz is terrible developers, not knowing how to implement it after an explanation is a red flag though.
jerf 5y ago
No, it's not FizzBuzz. It's a recursive algorithm, which FizzBuzz isn't. (Or doesn't have to be. Let's not cite crazy repos with dozens of solutions deliberately obfuscated.) That automatically takes it out of FizzBuzz range. If you're a functional programmer, it's probably something you can just bang out. I've done functional programming. But it's been a while. In an interview situation, I'd definitely need some time to struggle through it. What gives? I claim to be a senior developer of ~25 years experience? Why can't I just bang out the roughly ten-line solution it would be in Haskell, including the requisite data declarations? Well, in my 25 years of experience, yes, I've covered everything that is necessary to do that problem, but I've got to drag it out of storage and rehydrate it manually, because I don't do this sort of thing every day lately. Or ever, really, because what senior dev is running around implementing Computer Science 301 data structures every day anymore? Pretty much just one currently implementing a brand new language that needs those basic structures in its standard library. I'd get there. It wouldn't even necessarily take long. But I can understand why an interviewer asking this question ten times a week who knows the answer forward and backward might find taking even 5 minutes to be an unimpressive performance for something that such an expert should clearly just be able to scribble down in one shot, right? And I'm gonna be honest. If you ask me to balance a possibly-unbalanced sorted binary tree, I'm basically going to be re-deriving the answer from scratch. Yeah, I covered it. Probably even did a homework assignment on it in C. But my job for the past 25 years has not been implementing balanced binary trees.

SQueeeeeL 5y ago

Inverting a binary tree is essentially trivia in the context of most programming, honestly, if I had to do it without a library I'd be extremely worried I'd fuck it up in some subtle way. Max Howell obviously has a strong understanding of file systems, web protocols, package management, and a whole other suite of skills I'm too stupid to understand.

pydry 5y ago

The fact it was trivia irrelevant to most programmers is precisely why it was such a brain dead question. Asking what FizzBuzz is is similarly useless and would also make an abysmal question.

ClumsyPilot 5y ago

"until I found out what inverting a binary tree actually is" So do you consider youself a terrible, unhire-able developer? Presumable your still has quadrupled since you found out this information?

vultour 5y ago
No, but I assume that the inteviewer will elaborate if you ask them what they mean. I don't consider people who don't know what FizzBuzz is terrible developers, not knowing how to implement it after an explanation is a red flag though.

jerf 5y ago

No, it's not FizzBuzz. It's a recursive algorithm, which FizzBuzz isn't. (Or doesn't have to be. Let's not cite crazy repos with dozens of solutions deliberately obfuscated.) That automatically takes it out of FizzBuzz range. If you're a functional programmer, it's probably something you can just bang out. I've done functional programming. But it's been a while. In an interview situation, I'd definitely need some time to struggle through it. What gives? I claim to be a senior developer of ~25 years experience? Why can't I just bang out the roughly ten-line solution it would be in Haskell, including the requisite data declarations? Well, in my 25 years of experience, yes, I've covered everything that is necessary to do that problem, but I've got to drag it out of storage and rehydrate it manually, because I don't do this sort of thing every day lately. Or ever, really, because what senior dev is running around implementing Computer Science 301 data structures every day anymore? Pretty much just one currently implementing a brand new language that needs those basic structures in its standard library. I'd get there. It wouldn't even necessarily take long. But I can understand why an interviewer asking this question ten times a week who knows the answer forward and backward might find taking even 5 minutes to be an unimpressive performance for something that such an expert should clearly just be able to scribble down in one shot, right? And I'm gonna be honest. If you ask me to balance a possibly-unbalanced sorted binary tree, I'm basically going to be re-deriving the answer from scratch. Yeah, I covered it. Probably even did a homework assignment on it in C. But my job for the past 25 years has not been implementing balanced binary trees.