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Google's “Director of Engineering” Hiring Test

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Re: Google's “Director of Engineering” Hiring Test

#951

Post by oldcreek12 »

dvirsky wrote: post #363
TheCapn wrote: post #41

Earlier quoted context omitted.

The inode question gave me flashbacks to my interview with Amazon. They wanted me to explain what a hash function is. I kept giving answers for about 3 minutes explaining hashing, common algorithms, reasons to use it and places it applies. Recruiter: "I was looking for you to say it's a fingerprint " So I guess I was wrong, because despite explaining them in decent detail, I didn't use the one keyword.

On my phone screen a Google recruiter asked me "how much is 2^24", and I knew the answer by heart and answered immediately. So he asked "how did you figure this out so fast?". I told him I didn't, I just remember all the "important" powers of 2. He said "well... that's not what I was looking for, I wanted you to calculate it, but... I guess a candidate who memorizes powers of 2 is a positive sign?". I passed.

haha, I got that question too, in stead I worked in MPLS for over 5 years, I know by heart that MPLS label has 20bits which translates to 1 million labels, times 2^4 that is 16 million. The recruiter asked me how I figured it out so fast, I explained to him, that recruiter had no idea of what I was talking about. I did not pass.

Re: Google's “Director of Engineering” Hiring Test

#952

Post by bogomipz »

gcp wrote: post #560
greyman wrote: post #371

I once coded chess playing algorithm for fun, and can confirm that the recruiter was correct on #9: you count bits by using a lookup table and then sum the results. It's the quickest way. But I am not sure if this is possible to figure out immediately without such experience...

Ah, the appeal to authority. It depends, but generally speaking, you are wrong and OP is right that you'd want to benchmark on the actual architecture. a) First of all, you're probably basing your answer off of experience with 64-bit popcounts. But note the question was about popcounting multiple 16-bit words, not single 64-bit words. This isn't typically what you do in a chessprogram. b) The table has a cache footpr…

>"Lacking POPCOUNT, and with cache pressure, the SWAR approaches are good, especially if you can compute multiple results at once"

Can you explain what a SWAR approach is?

Re: Google's “Director of Engineering” Hiring Test

#953

Post by Klockan »

daveio wrote: post #884
Klockan wrote: post #878

Earlier quoted context omitted.

The messages contains a lot more than the flags though so those bytes aren't enough and he didn't mention SYN-ACK.

They're bits. SYN can be represented as 0x02, ACK can be represented as 0x10. 0x02 BITWISE-OR 0x10, ie SYN BITWISE-OR ACK or 'SYN-ACK' colloquially, is 0x12. "in hexadecimal: 0x02, 0x12, 0x10".

Those are just flags, the message contains much more than the flag. Therefore it is wrong to say that they just send the flags and that the flags are equivalent to SYN and ACK.

Re: Google's “Director of Engineering” Hiring Test

#954

Post by Klockan »

silentmars wrote: post #887
Klockan wrote: post #879

Earlier quoted context omitted.

No, I meant that the interviewee misunderstood the questions/answers given by the recruiter and thus misrepresented them when he wrote the blogpost. Since he couldn't even get the questions right I highly doubt that he gave a correct representation of the recruiters attitude as well.

Which of the following seems more likely? A recruiter who was already giving the guy the wrong interview, and whose job revolves essentially around HR and sales, made mistakes in asking a series of technical questions. An expert with decades of relevant technical experience misunderstands and confuses basic networking and system topics.

Which of the following seems more likely?

A person fails to read a question verbatim.

A person who has been the "smartest person in the room" for decades has an inflated view of his fluency on a topic and makes mistakes in his favor when he tries to reconstruct the questions from memory.

Re: Google's “Director of Engineering” Hiring Test

#955

Post by Klockan »

tptacek wrote: post #926
delroth wrote: post #848

Earlier quoted context omitted.

> You can't learn about someone's capabilities by putting them on the spot with trivia questions. But that's not the point of these questions. These questions are a 5-10min phone pre-screen before getting to the actual interviews. They test if the candidate has experience in a given field, not if they can search for information or what are the precise bounds of their capabilities. It's trivia, but it's trivia that is…

These screens pass people who can answer trivia but who can't effectively code, and they reject people who have a gift for solving engineering problems with code but who can't answer trivia questions when put on the spot. The ostensible reason they get deployed (I say "ostensible" because we all know that in reality the on-site interview consists of the same stupid kinds of questions) is to keep the employer from was…

> These screens pass people who can answer trivia but who can't effectively code, and they reject people who have a gift for solving engineering problems with code but who can't answer trivia questions when put on the spot.

SRE's are hired to fix outages and other problems asap, knowing trivia is very important then since at that point you might be losing a million dollars per second.

Re: Google's “Director of Engineering” Hiring Test

#956

Post by dvirsky »

oldcreek12 wrote: post #951
dvirsky wrote: post #363

Earlier quoted context omitted.

On my phone screen a Google recruiter asked me "how much is 2^24", and I knew the answer by heart and answered immediately. So he asked "how did you figure this out so fast?". I told him I didn't, I just remember all the "important" powers of 2. He said "well... that's not what I was looking for, I wanted you to calculate it, but... I guess a candidate who memorizes powers of 2 is a positive sign?". I passed.

haha, I got that question too, in stead I worked in MPLS for over 5 years, I know by heart that MPLS label has 20bits which translates to 1 million labels, times 2^4 that is 16 million. The recruiter asked me how I figured it out so fast, I explained to him, that recruiter had no idea of what I was talking about. I did not pass.

Well, I answered the rest of the questions perfectly and exactly like he expected, so it might have helped.

Re: Google's “Director of Engineering” Hiring Test

#957

Post by fatihky »

dewiz wrote: post #818
fatihky wrote: post #640

Earlier quoted context omitted.

I am not him, if you ask this.

I was referring to the author of the blog post. As far as I know there is just one person authoring GWAN web server. (funny thing the site is down, maybe given the traffic brought by HN, and I assume the web server hosting the blog is GWAN :-) )

yes, it is gwan :)

Re: Google's “Director of Engineering” Hiring Test

#958

Post by johnnyfaehell »

DannyBee wrote: post #152

FWIW: As a director of engineering for Google, who interviews other directors of engineering for Google, none of these are on or related to the "director of engineering" interview guidelines or sheets. These are bog standard SWE-SRE questions (particularly, SRE) at some companies, so my guess is he was really being evaluated for a normal SWE-SRE position. IE maybe he applied to a position labeled director of engineer…

> These are bog standard SWE-SRE questions (particularly, SRE) at some companies, so my guess is he was really being evaluated for a normal SWE-SRE position.

This makes the most sense to me, why would a director of engineering be responsible for getting Google back online if it went down when there are SREs.

Re: Google's “Director of Engineering” Hiring Test

#959

Post by throwawayIndian »

mikeash wrote: post #917
throwawayIndian wrote: post #913

Earlier quoted context omitted.

> It would be like an accountant not knowing what the number 4 is. It's a hypothetical no-go! Every person, even the fourth grader knows the number 4. So why ask a question that measures their ability to remember 4, say 4 or show that they know 4. > I don't see how a programmer could be remotely competent without having been exposed… Share this link with them: http://stackoverflow.com/questions/1517582/what-is-the-di…

Are you hiring fun people who know nothing about computers? Or are there actually more criteria than you let on here?

> hiring fun people…

Absolutely! This is super super important. Fun to work with, not annoying to waste time with.

> know nothing about computers

It's sad that you think this way of people who couldn't answer your questions at the expected level.

> Or are there actually more criteria than you let on here?

Yes! One way to know if they're any good or not suitable is by giving them a problem statement like so:

'Design X, feel free to choose a language that's suitable for this problem', and then may be proceed to hint with: 'You might want to look at advantages of Static versus dynamic typing'… and then let them ask whatever questions they want to ask or read up or search or start implementing whatever.

Observe what they do -- and how fast can they get to the decision of what language and why. And how to make X (break down of steps) or if they can dive and start making X there itself. Note, if they had theoretical knowledge of what you seek during an interview it will work to their advantage naturally. Or sometimes not.

Of course, this process may not work for you as it does for us -- therefore seeking direct answers about static vs dynamic language may not be such a bad question after all (I get it), but expecting people to accurately remember what an http request or its response looks like may not be fruitful at all. It can throw good people off guard and ruin the rest of the interview for them.

Re: Google's “Director of Engineering” Hiring Test

#960

Post by mirekrusin »

zerkten wrote: post #495
mirekrusin wrote: post #420

Earlier quoted context omitted.

It's an interesting recruitment setup where overqualified candidates are rejected.

You can have situations where you are prepared to recruit someone with potential versus being the final article. In those situations the overqualified candidates may not compare well with what you consider the potential of the slightly under-qualified candidate, and may not have some of their other attributes. It's obviously a risk, but it happens more than people think.

Still, overqualified candidate supersets qualified/unqualified. He/she should pass the test.

Failure of recognising overqualified candidate from under qualified is a failure on the recruiter side, not the candidate side.

Recruiter is of course allowed to say "I'm sorry, but you are well overqualified for this position". In this case he was falsely recognised as somebody under qualified.

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