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Google Interview Questions Deconstructed: The Knight’s Dialer

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Re: Google Interview Questions Deconstructed: The Knight’s Dialer

#41

Post by noarchy »

username90 wrote: post #20
noitpmeder wrote: post #12

Earlier quoted context omitted.

/r/iamverysmart/

What is your point? Companies wants to hire smart people which is why they have these interviews. This applies no matter what level people are at. "I forgot" isn't valid defense. All the people in these threads who says things like "I knew this but forgot" are really cringy.

The point may be that many (if they're truly senior, not someone with 3-5 years in the industry) will not have used these theories in 10+ years. The real-world application is questionable.

Re: Google Interview Questions Deconstructed: The Knight’s Dialer

#42

Post by CydeWeys »

throwaways885 wrote: post #13
joshuamorton wrote: post #4

Earlier quoted context omitted.

This isn't a brainteaser. It's a programming problem. Brainteasers are like "how many ping pong balls fit in a 747" or "you wake up an inch tall in a blender, the blades start spinning in a minute. How do you survive."

> how many ping pong balls fit in a 747 This one does seem useful. Being able to do back-of-the-napkin (i.e. fermi problem) calculations is a pretty good skill.

Google does still use questions like this, it's just that they're relevant to programming/system design. So a question might be "How many servers are needed to run Gmail?"

The reason the 747 question is bad is because it has little to do with programming and a lot to do with how much you happen to know about planes and ping pong balls and how to estimate volumes of irregularly shaped objects, none of which have much if any correlation with programming ability.

Re: Google Interview Questions Deconstructed: The Knight’s Dialer

#43

Post by pc86 »

thdc wrote: post #28
joshuamorton wrote: post #4

Earlier quoted context omitted.

This isn't a brainteaser. It's a programming problem. Brainteasers are like "how many ping pong balls fit in a 747" or "you wake up an inch tall in a blender, the blades start spinning in a minute. How do you survive."

I agree that this isn't a brainteaser. The problem itself appears to be nonsensical with no real world value but as long as it is a well defined problem with a concrete solution then it should be fine. Ideally the interviewer should be looking for how you approach the problem and what you do to obtain an answer (whether they do or not is a separate topic) Granted, the 747 question also technically does have a concret…

Now I'm just thinking about how I would survive in a giant blender.

Whether or not someone is about to add ice seems like a pretty important variable.

Re: Google Interview Questions Deconstructed: The Knight’s Dialer

#44

Post by xienze »

jeffbee wrote: post #29

It might not be obvious but these kinds of questions are terrible for diversity and inclusion because they incorporate too much cultural knowledge that is not universal. A person who has never seen chess will spend more of the interview just trying to figure out what is meant by the Knight's move. That disadvantages people from low-chess cultures, no matter how qualified and intelligent they may be. Chess also has a…

> A person who has never seen chess will spend more of the interview just trying to figure out what is meant by the Knight's move.

I mean he explicitly spells it out as part of the problem. I highly doubt in an interview they'll just plop down a term like "knight's move" and refuse to clarify what is meant by it, if necessary. It's not exactly the sort of thing that takes living a life of privilege to understand.

Re: Google Interview Questions Deconstructed: The Knight’s Dialer

#45

Post by notsuoh »

blahyawnblah wrote: post #33
jeffbee wrote: post #29

It might not be obvious but these kinds of questions are terrible for diversity and inclusion because they incorporate too much cultural knowledge that is not universal. A person who has never seen chess will spend more of the interview just trying to figure out what is meant by the Knight's move. That disadvantages people from low-chess cultures, no matter how qualified and intelligent they may be. Chess also has a…

I doesn't take long to understand how a knight moves, though. Move two squares in a direction and then move one square perpendicular to that.

Not hard, but still disadvantageous to people who haven't seen it before as that's one more thing they have to learn and keep in mind during a stressful interview.

Re: Google Interview Questions Deconstructed: The Knight’s Dialer

#47

Post by username90 »

defen wrote: post #19
username90 wrote: post #11

Earlier quoted context omitted.

The junior and the senior aren't competing for the same job though, this just checks that you still remember the theory you learned in college. And no, just because you are senior doesn't mean that you get a free pass forgetting everything you learned in college. I haven't practiced problems like this in over 5 years and I still ace them.

> this just checks that you still remember the theory you learned in college. Sure, but not everyone went to college or studied computer science / math. This seems like one of those problems that's really just testing a very specific type of preexisting knowledge.

You'll get full score even if you don't know the matrix solution, just doing a memoized recursive one is enough. However if you had that specific knowledge then they still test whether they have the skills to apply esoteric knowledge correctly which is also very valuable.

Anyway, Google no longer has this question. Once it gets known outside Google bans it from interviews. Sometimes people give banned questions but in general they don't and it is taken into account. I remember it being popular as a question 4 years ago, popular questions tend to leak quickly and get banned though.

Re: Google Interview Questions Deconstructed: The Knight’s Dialer

#48

Post by chromatin »

jeffbee wrote: post #29

It might not be obvious but these kinds of questions are terrible for diversity and inclusion because they incorporate too much cultural knowledge that is not universal. A person who has never seen chess will spend more of the interview just trying to figure out what is meant by the Knight's move. That disadvantages people from low-chess cultures, no matter how qualified and intelligent they may be. Chess also has a…

Given how primitive and easy to understand the movement constraints in this particular case are, this seems like an unnecessary concern. Note that I am not dismissing the rest of your post.

Re: Google Interview Questions Deconstructed: The Knight’s Dialer

#49

Post by pb7 »

jeffbee wrote: post #29

It might not be obvious but these kinds of questions are terrible for diversity and inclusion because they incorporate too much cultural knowledge that is not universal. A person who has never seen chess will spend more of the interview just trying to figure out what is meant by the Knight's move. That disadvantages people from low-chess cultures, no matter how qualified and intelligent they may be. Chess also has a…

This reads like satire. There is no chess knowledge involved. The constraint is that you can only dial in a 2x3 L-shape.

Edit: Typo, as opposed to the well known capital L-shape that is just one unit wide.

Re: Google Interview Questions Deconstructed: The Knight’s Dialer

#50

Post by CydeWeys »

jeffbee wrote: post #29

It might not be obvious but these kinds of questions are terrible for diversity and inclusion because they incorporate too much cultural knowledge that is not universal. A person who has never seen chess will spend more of the interview just trying to figure out what is meant by the Knight's move. That disadvantages people from low-chess cultures, no matter how qualified and intelligent they may be. Chess also has a…

I have a worse example of this -- I've seen a programming question going around that involves tournament brackets (specifically how they're seeded). I'm not particularly into sports, but if you were, you would have a huge leg up on this problem because you'd already have an intuitive sense of how brackets work and are constructed, that I wouldn't.
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