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Data structures and algorithms I actually used while working at tech companies

blog.pragmaticengineer.com

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Re: Data structures and algorithms I actually used while working at tech companies

#281

Post by noema »

dominotw wrote: post #274
midev wrote: post #269

Earlier quoted context omitted.

> because if everyone is asking whatever they want there is no way to compare one candidate to another. That's obviously not true.... > Most companies require interviewers to pick a question from their internal 'question bank' Again, having worked at some fairly big and respected companies, this has never been the case. I'm not interviewing for rote candidates. Everyone is different. Ergo, the questions are different…

> Again, having worked at some fairly big and respected companies, this has never been the case. https://leetcode.com/discuss/interview-experience?currentPag... Please take a look at these. I recently interviewed at FB and I got 2 questions in phone screen that were from leetcode with FB tag. > Everyone is different. Ergo, the questions are different. Facebook is running interview factory, they just don't have time t…

Does leetcode have some partnership with these companies or something? They're basically forcing you to pay their subscription fee to be competitive in in the candidate pool.

Re: Data structures and algorithms I actually used while working at tech companies

#282

Post by richthegeek »

decafninja wrote: post #256

I don't think the issue is DS&A or even leetcode problems in general. I think the problem is being expected to regurgitate* 1-2 hyperoptimal leetcode solutions in 45 minutes while suffering from heavy interview pressure. *by regurgitate, you can't simply implement the optimal solution either even if you know it. You have to put on a show where it seems like you're arriving at and iterating towards the optimal solutio…

It is rather ridiculous.

"These two guys spent 6 months thinking about this problem to come up with this algorithm. Now pretend like you can independently come up with an identical algorithm in 45 minutes."

Re: Data structures and algorithms I actually used while working at tech companies

#283

Post by holidayacct »

Drew_ wrote: post #276
holidayacct wrote: post #254

Earlier quoted context omitted.

If you're working on a large scale project you wouldn't be implementing a specific algorithm by yourself anyway. You'd be discussing a specific problem and then discussing the pros and cons of different algorithms that you want to implement and implementing POCs in different algorithms. The interview is just to see if you can think and discuss in terms of algorithms and data structures.

Technical interviews problems do sometimes actually resemble some discussions that happen in the real world however there are two major problems that I see in the interview space that don't have clear solutions: 1) one or two people in the discussion (interviewers) already know the perfect solution to the problem and are contributing as little as possible to the discussion. 2) the actual amount of allotted time to br…

I'm completely in favor of randomized interview questions. My personal favorite approach is a two-way interview. You get to ask a technical interview question of the person you're interviewing with. If they ask you a ridiculous question, they get hit with a ridiculous question also. As an employer you could monitor this and see if you're employees are giving unfair questions to candidates they can't answer themselves. It would also be a good idea for HR to record all of these interviews so they can have someone knowledgeable judge the interview process and track the performance of new hires versus the questions they are asking. If the interviewer starts having problems answering their own difficulty level in questions then maybe they should be looking for a new job also. I was once asked a ridiculous question and threw an interviewer off by asking them how many times they had actually implemented something like they were asking, they stopped talking immediately.

My personal opinion is that all of this should be scrapped in favor of seeing what the person has produced and having them partially implement a solution of something they have written in the past. It is a virtual impossibility that anyone could work on a project of any sort without being able to sit down for an 8 hour interview where they are responsible for partially re-creating something they have worked on in the past. To this day I still remember large parts of source code I've worked on 10 years in the past.

Re: Data structures and algorithms I actually used while working at tech companies

#284

Post by syndacks »

notacoward wrote: post #273
wenc wrote: post #264

Earlier quoted context omitted.

> Resistance to anxiety. This disadvantages women, minorities, and people with psychological conditions that should be covered by ADA. I resemble some of those categories, and I don't know if I would feel comfortable making the leap to correlate them to a some inherent reduced level of resistance to anxiety. That seems like a generalization which I feel that, on an aggregate level, seems unsupportable by data. I thin…

Allow me to elaborate, then. There's an inherent power dynamic in interviews, which creates stress in the interviewees. That effect is magnified for anyone who is unlike their interviewers, who still tend to be white and male. It's magnified still further when the power dynamic within the interview reflect the one that - very unfortunately - still persists in society at large. Lastly, the funny thing about stress/anx…

>Is any of that even controversial enough to require citation?

I'm sorry, excuse me? Are you saying that non-minority, non-women don't suffer anxiety? Your parent comment certainly seems to suggest that. Which, at a minimum, is flat out wrong. Educate yourself[0]. And then zoom out and ask yourself why it's not only permissible, but often lauded, to so flippantly say what you just said.

[0] - https://www.apa.org/about/policy/boys-men-practice-guideline...

Re: Data structures and algorithms I actually used while working at tech companies

#285

Post by karmakaze »

Drew_ wrote: post #276
holidayacct wrote: post #254

Earlier quoted context omitted.

If you're working on a large scale project you wouldn't be implementing a specific algorithm by yourself anyway. You'd be discussing a specific problem and then discussing the pros and cons of different algorithms that you want to implement and implementing POCs in different algorithms. The interview is just to see if you can think and discuss in terms of algorithms and data structures.

Technical interviews problems do sometimes actually resemble some discussions that happen in the real world however there are two major problems that I see in the interview space that don't have clear solutions: 1) one or two people in the discussion (interviewers) already know the perfect solution to the problem and are contributing as little as possible to the discussion. 2) the actual amount of allotted time to br…

> the only outcome is that more candidates would perform very well and that's not an outcome companies actually want unfortunately

Why would this be the case--at places where the number of candidates far exceed positions? This is the exception rather than the common case.

Re: Data structures and algorithms I actually used while working at tech companies

#286

Post by inancgumus »

The problem with interviews is not whether those companies are actually using algos in practice. The problem is that they ask the data structures and algorithms as ruthless puzzless to detect a candidate's level. That's a very wrong approach.

Re: Data structures and algorithms I actually used while working at tech companies

#287

Post by spelunker »

notacoward wrote: post #257
whack wrote: post #228

I'm increasingly convinced that Algorithms-and-Data-Structure interviews are essentially being used as a proxy for: - General IQ. Can this person understand and apply complex ideas - Grit. Is this person hard-working enough to learn things that take time and effort It's the software equivalent of the NFL scouting combine. The goal is not to create a test that is similar to the day-to-day job. But rather, create a tes…

Unfortunately, those kinds of interviews also select for some other things that they shouldn't. * Youth. People who have very recently studied these things in school, and use the same languages as the interviewers, have an advantage. * Free time. People who have families (for example) might have less free time to study "Cracking the Code Interview" and such. * Absence of anxiety. This disadvantages women, minorities,…

Just curious, what are some examples of better ways to measure general IQ and grit? You said they are questionable concepts, so how do _you_ interview people?

Re: Data structures and algorithms I actually used while working at tech companies

#288

Post by ralfhn »

Algorithms and data structures are very useful and a general knowledge is certainly required. However, when you're facing a problem, do you have to come up with an optimal solution, on a whiteboard, in 45 minutes, and with someone looking over your shoulder?

Re: Data structures and algorithms I actually used while working at tech companies

#289

Post by whalabi »

syndacks wrote: post #284
notacoward wrote: post #273

Earlier quoted context omitted.

Allow me to elaborate, then. There's an inherent power dynamic in interviews, which creates stress in the interviewees. That effect is magnified for anyone who is unlike their interviewers, who still tend to be white and male. It's magnified still further when the power dynamic within the interview reflect the one that - very unfortunately - still persists in society at large. Lastly, the funny thing about stress/anx…

>Is any of that even controversial enough to require citation? I'm sorry, excuse me? Are you saying that non-minority, non-women don't suffer anxiety? Your parent comment certainly seems to suggest that. Which, at a minimum, is flat out wrong. Educate yourself[0]. And then zoom out and ask yourself why it's not only permissible, but often lauded, to so flippantly say what you just said. [0] - https://www.apa.org/abou…

> I'm sorry, excuse me? Are you saying that non-minority, non-women don't suffer anxiety?

To be fair, OP did say "That effect is magnified for anyone who is unlike their interviewers"

But, I do agree some evidence from OP would help their claims.

I wouldn't be surprised if minorities experience more anxiety, on average, in situations like an interview, though. I think it's established that imposter syndrome is more frequently encountered for example but it's too late here to go digging for evidence :)

Re: Data structures and algorithms I actually used while working at tech companies

#290

Post by notacoward »

cmrdporcupine wrote: post #277

Last I looked we are still in a market where there is supposedly more open positions than there are engineers to fill them. So why are firms that are hiring so obsessed with producing more and more arcane barriers to entry? As I always comment when this topic comes up: this process makes some sense at Google (where I work) where the sheer number of applicants is massive and false-negatives are perfectly fine because…

Take an interviewer who has the benefit of having worked through a problem literally a hundred times, further aided by internal training that represents thousands of iterations. Have them judge someone who hasn't had to solve that particular problem more than once or twice, twenty years ago in a different language (and certainly not on a whiteboard). That interviewer will form an inaccurate opinion of the interviewee's relative ability. Not maybe, and not by a little. Any interview process that does nothing to correct for that is broken.
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