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Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

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Re: Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

#81

Post by ryandrake »

habosa wrote: post #36

I work at Google and no it's not easy for us either. I've heard many of my coworkers joke that if they went through the interview process again they'd probably fail. That said I see two kinds of interviewers. One kind (the good kind) takes a medium difficulty question and uses it to explore the candidate's coding, algorithms, communication, and problem solving skills. The other kind has a super hard question with a s…

> I've heard many of my coworkers joke that if they went through the interview process again they'd probably fail.

I’ve heard this joke at a lot of tech companies. Also, “the hardest thing I’ve ever done at my job was pass the interview.” Just shows how divorced from day-to-day work skills interviewing has become.

I think most tech companies severely overestimate the cost of false positives, particularly in the USA where it’s trivially easy to fire someone who turns out to be a dud.

Also think it represents an opportunity: if you could reliably figure out who made it to the interview stage at these top companies but did not get an offer, you could forego your recruiting expense, simply hire all those people and likely end up with a well above average team, minus the few false positives.

Re: Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

#82

Post by sadamznintern »

tinderliker wrote: post #42

I am a SWE at Google, and yes, most Googlers are pretty good at solving whiteboard problems. It's not like we are born with those solutions in our heads, but we enjoy solving those questions especially with other people. It's a lot of fun to "explore" answers to these questions, and that's what I think interviews are all about. I know HN hates whiteboard problems, but just like anything, you get good with it if you'r…

How do I force myself to find them fun?

Re: Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

#83

Post by hzay »

sadamznintern wrote: post #79
hzay wrote: post #75

I worked for FB. I like the whiteboard problems and many other engineers like them too, and I enjoyed discussing or solving similar problems over lunch. That's probably why they're so prevalent in interviews -- I don't believe they actually predict a candidate's success in a company. Btw in college, I used to compete on websites like topcoder, spoj, etc for fun. The interview processes of many companies drastically f…

How do I force myself to find doing those problems to be fun? To me they just seem painful because they really expose how stupid I am even if I know he basics.

It's okay if you don't find these problems to be fun. Some people like crossword puzzles, some don't. If you can't solve a problem, it doesn't say anything about you, except that you haven't yet practiced using that particular algorithm/technique enough. It most definitely does not say that you are stupid, although some ppl would have you believe that.

I'd recommend that you only solve problems that are extremely easy, on websites like https://www.spoj.com or https://www.topcoder.com or old google code jam questions. Pick a single website (I recommend codejam) and do only the easy ones for a few months. It's hard to argue against the happiness that comes when your program passes the tests. The point is not to sharpen your skill but to get used to the feeling that your program passes ALL the tests cases.

If you get to a stage where you're completely sick and bored of easy problems, pick a slightly more difficult problem with basic algorithms like plain BFS or DFS. Try it for just a day or two and when you can't solve it, read the published solution. Try to understand it, apply it manually to the test cases and once you're sure that you've completely grasped the solution, implement it and see if it passes all the tests cases. Take it slowly, and return to easy problems often.

This could take you pretty far in terms of enjoying the process. :) At least that's how it worked with me -- I liked the high of getting a program "accepted".

Re: Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

#85

Post by q845712 »

lynal wrote: post #32
Silhouette wrote: post #24

Earlier quoted context omitted.

Indeed, although it's not unheard of for mathematics lecturers at university to throw in a question within a twenty-question problem sheet for their course that is actually equivalent to some important unsolved problem, on the off chance that one of their students sees things in a totally new way and makes a ground-breaking discovery. Solving something NP-hard in linearithmic time would certainly qualify...

Do you have a cite/example of a lecturer doing that on an exam? Are there any examples where that has been successful? I had never heard of that happening! It would be extremely cool if it ever worked.

i audited university of Chicago's undergrad "hard-track" real analysis (i forget the name, but iirc there was an easier version of the course available).

The problem sets would have several questions you were expected to solve, and then often 1-3 questions marked with 1 or 2 stars. I forget exactly the language, but there was some explanation that you probably couldn't solve the 1-star problems, and solving the two-star questions could be someone's PhD thesis, as it would require novel insight into an unsolved problem.

The point was that it was a class for young aspiring mathematicians many of whom were used to being the smartest person around, and this helped them confront problems they couldn't solve without feeling like total failures. Also at that kind of school, you never know, someone might be able to solve one.

Re: Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

#86

Post by jasondclinton »

thewarrior wrote: post #78
jasondclinton wrote: post #26

Earlier quoted context omitted.

I kinda agree but think that you are overselling the signal generated. We have internal data that we can't discuss here that throws some doubt on the signal from whiteboard interviews of the type described above.

What CAN you tell us about the internal data ? Why does the process persist if there's data showing its flawed ?

Cribbing from a famous quote: this interview methodology is the worst except for all of the others. We don't know what a systemic, better interviewing system would be.

Re: Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

#87

Post by zeveb »

ryandrake wrote: post #81
habosa wrote: post #36

I work at Google and no it's not easy for us either. I've heard many of my coworkers joke that if they went through the interview process again they'd probably fail. That said I see two kinds of interviewers. One kind (the good kind) takes a medium difficulty question and uses it to explore the candidate's coding, algorithms, communication, and problem solving skills. The other kind has a super hard question with a s…

> I've heard many of my coworkers joke that if they went through the interview process again they'd probably fail. I’ve heard this joke at a lot of tech companies. Also, “the hardest thing I’ve ever done at my job was pass the interview.” Just shows how divorced from day-to-day work skills interviewing has become. I think most tech companies severely overestimate the cost of false positives, particularly in the USA w…

> I think most tech companies severely overestimate the cost of false positives, particularly in the USA where it’s trivially easy to fire someone who turns out to be a dud.

I don't think that's actually true. People who are net-negative on a team may be very personable and hence emotionally difficult to fire. And of course the U.S. does have a number of protected classes, who can be very difficult & expensive to fire for cause (because the assumption is that they were not fired for cause). I'm a member of a protected class, and I often worry that it actually makes it more difficult for me to get hired: will folks be willing to take a chance on me, knowing that were I a jerk I could make life difficult for them? I'm not a jerk (I think!), but they can hardly know that!

Re: Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

#88

Post by kjeetgill »

The question I recently got that I found annoying was this: Given input (4, 2, 3, -1, 5) and output (-30, -60, -40, 120, -24) what's the function between them?

I don't actually mind doing whiteboard interviews even on minimal prep. I've gotten a few of the "flagship" company offers and failed a few. I think part of it is internalising that nothing is going to guarantee you anything. You can always hit a question you bomb on and have an interviewer that will move on or bury you for it.

Phone screens are 2-4 questions and on-sites can add another 6-10. A 5% bomb rate for an on-site question will put you into the 60-70% pass rate.

I'm confident that if I do all the interviews I'll land atleast one offer but if you're putting all your eggs in one basket you're going to have a rough go of it.

Re: Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

#89

Post by lordCarbonFiber »

LandR wrote: post #21
octorian wrote: post #16

Earlier quoted context omitted.

> There is nothing about learning how basic data structures and algorithms work that won't help you in your day to day development. Having a basic understanding of these things is NOT the same as being able to regurgitate them on a whiteboard, under the stress of the interview process.

Exactly, I don't need to know this stuff of the top of my head. I can look it up...

The reason we test for things is to verify you have enough domain knowledge to "look it up". A bad interviewer will ask you to write quick sort on the board, because if we've already gotten to the point of "implement quick sort" yeah we can just look that up. However, if you're given a collection of nodes and asked to do something with them; that's a bit more interesting. If you know nothing about graph traversal, or have never seen a tree (both not uncommon in people claiming to be principle engineers in my industry) how do you even know what to search for? Best case is you're smart and waste time coming up with a new solution from first principles; most likely it just never gets done.

Re: Ask HN: Can engineers from Google or Facebook solve whiteboard questions easily?

#90

Post by yomansat »

franzwong wrote: post #69
tinderliker wrote: post #42

I am a SWE at Google, and yes, most Googlers are pretty good at solving whiteboard problems. It's not like we are born with those solutions in our heads, but we enjoy solving those questions especially with other people. It's a lot of fun to "explore" answers to these questions, and that's what I think interviews are all about. I know HN hates whiteboard problems, but just like anything, you get good with it if you'r…

I also want to see how you guys solve these problems. People on youtube videos already know the answer. They just told you how to solve it. But I can't see how they approach to get the answer. I think that part is the most interesting and valuable part for non-talent like me.

Here's one: https://www.youtube.com/watch?v=XKu_SEDAykw&t=11s
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