Why do big companies ask unrealistic software engineering interview questions?

The answer is usually self selection and calibration at scale. Self selection is about people looking like minded colleagues. If everybody is crazy about solving riddles and participates in programming competitions that's what they would be looking for.

Now, about the scale. Anything run at scale needs standardisation. You need to hire 100 senior developers. How do you know they have more or less same level? If every single interview is hand crafted, you'll either need to get all devs envolved (and not everybody is good at coming up with interview questions) or get standard questions and answers to allow a smaller group of people to deal with candidates and coding puzzles fit great there because they're slef contained and isolated. Every realistic question has multiple facets and that's what you get at the system design interview step.

Another problem I've observed was that the more you give the same puzzles to candidates, the easier they look to you. What the means is that you as an interviewer either need to keep your self in check regarding your reactions or you're risking giving a bad interview score in situations where it's not really warranted or there is a chance that the next question you take will be the one you find more complex (to be equal to position level in your head) and that would push the level of questions up. That's another observation I had when some interview questions would become so complex that I knew some of the existing devs would fail the interview for sure.

Does that give good results on the other end? I don't know, but what we definitely know is that there is the whole industry around leetcode to train peeople to pass these challenges specifically and that means that they only thing the interviewer know is that the candidate has put some effort to prepare for the interview meaning they're motivated to join the company. And maybe it's not the worst data point! Some companies actually explicitly mention this fact on their hiring pages.

To add to it, big corps have different ways to make interviews objective in whatever sense they think and that by definition reduces the personal impact. "Why did you ask this question? We've never done it before, we'll need to have a group call to calibrate". After a handful conversations like this you'll just stick to the standard process.

Is there a way to come up with a more human approach? Personal recommendations with some skin in the game I guess. I'm sure in some niche areas like browser engines all good devs know each other well and no interview is often necessary.

Yep. Strong negative signal from me. I can’t remember the last time I actually clicked the link. Anyone that thinks that the Medium experience is remotely acceptable is living in a world very different to mine. Just as importantly, the quality does tend to be crappy off-cuts from someone with an obvious content creator fetish.

Still better than posting on Twitter in fragments 1/9

Whiteboard coding used to be common but I haven't run a whiteboard interview for over a decade. I don't know how many companies still do that, but it's definitely a bad idea. You want to see how well a candidate knows their tools, and they will be more comfortable working in an editor, so it's a win/win to do that. Also if you do coding interviews from home it's easier for candidates and they're in a more comfortable environment.

So yeah I'm sure some firms do this, but there are plenty of others that don't.

Could not read the whole article but get the gist. Time was that I would have agreed. But I have changed position.

Candidates: you need to appreciate how difficult it is to hire good people, the dishonesty of many candidates, and how limited the tools are for identifying talent and filtering out weasels. It is true: party trick Big O questions have low utility in most jobs. It is true: there is talent out there which sucks at Big-O questions. It is true: there are people who are good at little else than the party tricks. Nevertheless: those questions provide an objective judgement about a candidate. That objective judgement is valuable.

You spent several years doing a degree to make yourself employment-compatible. You will be able to achieve this standard in far less time, and there are cash rewards at the end of it. Accept that you will need to burn 1-2 months to develop this capability, and that you will feel awesome once you have.

Get /Cracking the Coding Interview/. I was not impressed by the object-oriented design chapter, but seek to master the other first-11 chapters. Take what you need from the remaining chapters. Develop a set of flashcards. Find problems online. Work intensively for at least two weeks but ideally a month. Then book some interviews at firms where you don't mind if you fail. Some of the FAANGs have awesome pre-interview study material. Try to get into process with a firm like that. Keep training on your flashcards and doing a few problems a day to keep in form. Expect to struggle with early interviews. Learn from those experiences. Revise what you made a mess of, keep working with your flashcards until you have mastered your weak areas. Now start applying at the firms where you want to succeed.