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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

#11

Post by username90 »

defen wrote: post #6
username90 wrote: post #2

Counting the number of paths when you have loops is easiest using a connection matrix and matrix exponentiation. Then you get log(n) time.

I think this hits on why these types of problems are potentially bad. You could be the world's worst software engineer , but if you'd taken a graph theory course recently, you'd pattern match this, say "sure, can I use Matlab?" and be done in under 10 minutes. Or you could have tons of experience deploying robust production systems but have never happened to learn / need to use dynamic programming, in which case comi…

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.

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

#12

Post by noitpmeder »

username90 wrote: post #11
defen wrote: post #6

Earlier quoted context omitted.

I think this hits on why these types of problems are potentially bad. You could be the world's worst software engineer , but if you'd taken a graph theory course recently, you'd pattern match this, say "sure, can I use Matlab?" and be done in under 10 minutes. Or you could have tons of experience deploying robust production systems but have never happened to learn / need to use dynamic programming, in which case comi…

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.

/r/iamverysmart/

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

#13

Post by throwaways885 »

joshuamorton wrote: post #4
warmfuzzykitten wrote: post #3

Typical brain-teaser interview question that will have absolutely no correlation to on-the-job performance but makes the interviewer feel really smart. I thought Google had gotten away from these.

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.

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

#14

Post by happytoexplain »

username90 wrote: post #9
warmfuzzykitten wrote: post #3

Typical brain-teaser interview question that will have absolutely no correlation to on-the-job performance but makes the interviewer feel really smart. I thought Google had gotten away from these.

This isn't a brain teaser, they actually correlate with on-the-job performance. When I worked at Google I looked up their internal reports on the subject and they showed that the score people got on these algorithm interviews correlated pretty well with their performance ratings after they got hired. In other words the group of people who got hired even though they had low scores performed significantly worse than th…

Personally, I don't think correlation is good enough. I never doubted that people who are good with a single given abstract problem are correlated with people who are good candidates. So yes, it non-arbitrarily identifies good candidates, but it also arbitrarily eliminates a significant chunk of good candidates.

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

#16

Post by gcheong »

username90 wrote: post #9
warmfuzzykitten wrote: post #3

Typical brain-teaser interview question that will have absolutely no correlation to on-the-job performance but makes the interviewer feel really smart. I thought Google had gotten away from these.

This isn't a brain teaser, they actually correlate with on-the-job performance. When I worked at Google I looked up their internal reports on the subject and they showed that the score people got on these algorithm interviews correlated pretty well with their performance ratings after they got hired. In other words the group of people who got hired even though they had low scores performed significantly worse than th…

How do they control for bias in that a person with a high or low score may just be perceived to do better or worse, may be given better or less opportunities, etc. if their scores are known to the managers, etc? In other words it’s a correlation but is is explanatory?

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

#17

Post by username90 »

happytoexplain wrote: post #14
username90 wrote: post #9

Earlier quoted context omitted.

This isn't a brain teaser, they actually correlate with on-the-job performance. When I worked at Google I looked up their internal reports on the subject and they showed that the score people got on these algorithm interviews correlated pretty well with their performance ratings after they got hired. In other words the group of people who got hired even though they had low scores performed significantly worse than th…

Personally, I don't think correlation is good enough. I never doubted that people who are good with a single given abstract problem are correlated with people who are good candidates. So yes, it non-arbitrarily identifies good candidates, but it also arbitrarily eliminates a significant chunk of good candidates.

Yeah, it eliminates a lot of good candidates. If you can't match Google on benefits then you should not copy their hiring strategy and get their rejects, instead try to get the diamonds their rough process misses by doing something different.

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

#18

Post by nitwit005 »

defen wrote: post #6
username90 wrote: post #2

Counting the number of paths when you have loops is easiest using a connection matrix and matrix exponentiation. Then you get log(n) time.

I think this hits on why these types of problems are potentially bad. You could be the world's worst software engineer , but if you'd taken a graph theory course recently, you'd pattern match this, say "sure, can I use Matlab?" and be done in under 10 minutes. Or you could have tons of experience deploying robust production systems but have never happened to learn / need to use dynamic programming, in which case comi…

I wouldn't be surprised if people occasionally re-create famous math problems, given how many interview questions seem to get created these days.

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

#19

Post by defen »

username90 wrote: post #11
defen wrote: post #6

Earlier quoted context omitted.

I think this hits on why these types of problems are potentially bad. You could be the world's worst software engineer , but if you'd taken a graph theory course recently, you'd pattern match this, say "sure, can I use Matlab?" and be done in under 10 minutes. Or you could have tons of experience deploying robust production systems but have never happened to learn / need to use dynamic programming, in which case comi…

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.

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

#20

Post by username90 »

noitpmeder wrote: post #12
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.

/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.
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