4 ms·

While this is really interesting and I'll probably read through all of them just to brush up on my graph knowledge... but "Interview Questions"? Does anyone re

by throwaway2016a 10y ago

While this is really interesting and I'll probably read through all of them just to brush up on my graph knowledge... but "Interview Questions"? Does anyone really ask you to write this kind of code in interviews? They feel more like Computer Science homework questions.

coder007 10y ago
>Does anyone really ask you to write this kind of code in interviews Whoh!! All big IT companies ask these type of questions.. but mostly to graduate students and less experienced candidates.. but some companies might ask it to a 10 year old programmer as well..
- throwaway2016a 10y ago
  > All big IT companies ask these type of questions. Careful with absolutes. Although I used the word "any" in my post so I guess I shouldn't talk. Having worked at some large tech companies I can say definitely it is not "all" Some of these examples are 90+ lines of code which is why I ask. It would not be unrealistic with that much code that candidate will be sitting in the interview room for a half hour+ coding just one question. Several of these are borderline trick questions or only test your ability to memorize. For example, I learned Dijkstra’s algorithm in school 10+ years ago but if you were to ask me to implement it without reading the algorithm I wouldn't be able to. Asking graph data structure questions, sure. But here are more effective ways to know if a candidate will be a good fit than asking them to implement one of these. Use these as your interview test questions and all you are testing is the ability for the candidate to regurgitate algorithms. None of these test creative problem solving.
  - adrianratnapala 10y ago
    The thing about Dijkstra's algorithm is that it't just the obvious one that you would think of if you had never been introduced to the problem before. I'm pretty sure I "invented" it myself at least twice, and then forgot it. Kudos to Dijkstra for nailing it down, but I think we do students a disservice by invoking his name all the time, thus making it seem scary.
    - setr 10y ago
      >Kudos to Dijkstra for nailing it down, but I think we do students a disservice by invoking his name all the time, thus making it seem scary. Ofc, going the other way, once they realize Djikstra's algo is simple makes every other named algo less scary And finally they (hopefully) realize such naming is a stupid thing to be scared by and disregard it entirely
- Jtsummers 10y ago
  > but some companies might ask it to a 10 year old programmer as well.. I'm glad I wasn't interviewing at 10. I could program, but couldn't have handled any of these algorithms.
- sospep 10y ago
  not saying these companies[0] wont ask these types of questions, but at least they wont ask you to answer them on a whiteboard [0] https://github.com/poteto/hiring-without-whiteboards https://github.com/poteto/hiring-without-whiteboards related HN discussion thread[1] [1] https://news.ycombinator.com/item?id=13874026 https://news.ycombinator.com/item?id=13874026
gaastonsr 10y ago
You would be surprised.
wh-uws 10y ago
Yeah honestly anything after number 6 (bfs and dfs to be more specific) you would not be asked or really even have time for in an interview. Unless of course you are interviewing for a graph heavy job. Very interesting stuff though. Love graph algorithms have coded many myself in JavaScript to prep for interviews. edit source: my algorithms code base test suite https://travis-ci.org/williscool/code_gym/jobs/129218676 https://travis-ci.org/williscool/code_gym/jobs/129218676
- awesomepantsm 10y ago
  To be fair, almost all the problems after 6 are just variations on BFS and DFS, just different ways to ask the question. For example, (11. Check if an undirected graph contains cycle or not) can easily be solved by just performing a DFS with some exit conditions.
- deleted 10y ago
  [deleted]
- objclxt 10y ago
  > Love graph algorithms have coded many myself in JavaScript to prep for interviews. ...but have you coded any in JavaScript after the interview as part of the job? I suspect for most people the answer is no. It has always seemed strange to me to ask a topic that you're never going to encounter during your day to day work (yes, I know for some roles this isn't true).
  - cheriot 10y ago
    Lawyers and doctors don't do LSAT and GMAT questions on the job. It's not a problem specific to tech. An interview is a performance test. It's popular to say an interview should be like a day at work, but when we performance test our code, we don't throw an average load at it and say it's ready.
  - closeparen 10y ago
    I think there's a general consensus that mastering the specific material you would encounter in an undergraduate CS program proves you have the more general cognitive skills necessary to succeed in any entry-level programming job. We just don't trust the university to say that you've done the projects and sat the exams and demonstrated competence (what it's doing when it issues a degree), so each company unwraps that abstraction and runs its own projects and exams on the same material. But it is fundamentally based on college curricula. Trusting universities is likely out of the question. Eventually, I expect the industry will create something like the Bar Exam so each candidate can pass a trusted test once upon graduation (or even without going to college), rather than creating the burden for each company to do all that grading.
notyourloops 10y ago
The last interview I went on was almost an entire work day full of computer science and programming questions, with a break for lunch.
- bogomipz 10y ago
  That sounds pretty horrible, could you share what company this was?
  - objclxt 10y ago
    A full day of those kind of questions is pretty much the standard for the usual suspects (FB, Apple, Google, etc). Sometimes you might get a more generic design question thrown in.
    - stevenwoo 10y ago
      I interviewed at Apple a few years ago and was not asked the whiteboard programming questions (that I got asked at Google/Netflix/every game company) for a programming position.
  - notyourloops 10y ago
    I don't want to share the name, but it wasn't a typical tech giant, and the position was advertised as closer to entry-level as far as programming experience went. Toward the end of the day, the last interviewer grilled me hard and I cracked under the pressure. It actually had been going well until the last two interviews (out of 5 or 6), in which one person asked me an unreasonably challenging problem (definitely not feasible for a whiteboard) and the other was not pleasant to interact with (almost confrontational the whole time; I felt on the defensive). Prior to those, it was a healthy balance of reasonable challenge and solid conversation with engineers. It seemed like a cool place to work but their interviewing arrangement was brutal. I hope not to repeat that when I go looking again.
- deleted 10y ago
  [deleted]
Jach 10y ago
Like another commenter I think pretty much anything after DFS/BFS is asking a bit much during a normal interview. Floyd-Warshall? I guess it might be doable if you have a mathematical description handy, I've only implemented it once for a school assignment and don't remember how long it took but it's not something I'd ask or expect to be asked... I sometimes get asked to do interviews, I'm always torn by a desire to shake things up with the broken interview process but also somewhat conform to management expectations and feedback I can give like "was able to solve Arbitrary Parts of Arbitrary Programming Challenge X." In phone screens I spend ~10 mins on data structures, I'll ask some graph representation questions if they seem like they don't have an issue with others. In longer settings (at least an hour) and especially if I know other interviewers are asking other things I'll ask them to solve a problem and actually write code on a computer. A problem I sort of like is https://leetcode.com/problems/jump-game/#/description https://leetcode.com/problems/jump-game/#/description While I think there's a pretty simple solution that just loops over every element, what I did when I tried solving it myself was recognize it's a search problem and apply the generic search algorithm to it. (Create a frontier list with an initial starting point. Create a seen/visited set. While the list isn't empty, pop an item off. If it's what you're looking for, you're done. Mark it seen, expand its children and for each one add it to the frontier list if it hasn't already been seen.) Knowing the generic (iterative) algorithm is to me more important than the particulars of DFS/BFS (you can control which one by choice of data structure), I just want to visit all reachable nodes in my search space and it works. Of the several people I've given this to only one has solved it, and by solve I mean had any right approach even if non-compiling/terrible code. (They ended up using a BFS approach.) They also are a promotion level above mine and have had more years of experience. So maybe I need to retire it, but I still like the idea of seeing if someone can recognize a search problem and solve it because there are usually many ways of solving search problems.

coder007 10y ago

>Does anyone really ask you to write this kind of code in interviews Whoh!! All big IT companies ask these type of questions.. but mostly to graduate students and less experienced candidates.. but some companies might ask it to a 10 year old programmer as well..

throwaway2016a 10y ago
> All big IT companies ask these type of questions. Careful with absolutes. Although I used the word "any" in my post so I guess I shouldn't talk. Having worked at some large tech companies I can say definitely it is not "all" Some of these examples are 90+ lines of code which is why I ask. It would not be unrealistic with that much code that candidate will be sitting in the interview room for a half hour+ coding just one question. Several of these are borderline trick questions or only test your ability to memorize. For example, I learned Dijkstra’s algorithm in school 10+ years ago but if you were to ask me to implement it without reading the algorithm I wouldn't be able to. Asking graph data structure questions, sure. But here are more effective ways to know if a candidate will be a good fit than asking them to implement one of these. Use these as your interview test questions and all you are testing is the ability for the candidate to regurgitate algorithms. None of these test creative problem solving.
- adrianratnapala 10y ago
  The thing about Dijkstra's algorithm is that it't just the obvious one that you would think of if you had never been introduced to the problem before. I'm pretty sure I "invented" it myself at least twice, and then forgot it. Kudos to Dijkstra for nailing it down, but I think we do students a disservice by invoking his name all the time, thus making it seem scary.
  - setr 10y ago
    >Kudos to Dijkstra for nailing it down, but I think we do students a disservice by invoking his name all the time, thus making it seem scary. Ofc, going the other way, once they realize Djikstra's algo is simple makes every other named algo less scary And finally they (hopefully) realize such naming is a stupid thing to be scared by and disregard it entirely
Jtsummers 10y ago
> but some companies might ask it to a 10 year old programmer as well.. I'm glad I wasn't interviewing at 10. I could program, but couldn't have handled any of these algorithms.
sospep 10y ago
not saying these companies[0] wont ask these types of questions, but at least they wont ask you to answer them on a whiteboard [0] https://github.com/poteto/hiring-without-whiteboards https://github.com/poteto/hiring-without-whiteboards related HN discussion thread[1] [1] https://news.ycombinator.com/item?id=13874026 https://news.ycombinator.com/item?id=13874026

gaastonsr 10y ago

You would be surprised.

wh-uws 10y ago

Yeah honestly anything after number 6 (bfs and dfs to be more specific) you would not be asked or really even have time for in an interview. Unless of course you are interviewing for a graph heavy job. Very interesting stuff though. Love graph algorithms have coded many myself in JavaScript to prep for interviews. edit source: my algorithms code base test suite https://travis-ci.org/williscool/code_gym/jobs/129218676 https://travis-ci.org/williscool/code_gym/jobs/129218676

awesomepantsm 10y ago
To be fair, almost all the problems after 6 are just variations on BFS and DFS, just different ways to ask the question. For example, (11. Check if an undirected graph contains cycle or not) can easily be solved by just performing a DFS with some exit conditions.
deleted 10y ago
[deleted]
objclxt 10y ago
> Love graph algorithms have coded many myself in JavaScript to prep for interviews. ...but have you coded any in JavaScript after the interview as part of the job? I suspect for most people the answer is no. It has always seemed strange to me to ask a topic that you're never going to encounter during your day to day work (yes, I know for some roles this isn't true).
- cheriot 10y ago
  Lawyers and doctors don't do LSAT and GMAT questions on the job. It's not a problem specific to tech. An interview is a performance test. It's popular to say an interview should be like a day at work, but when we performance test our code, we don't throw an average load at it and say it's ready.
- closeparen 10y ago
  I think there's a general consensus that mastering the specific material you would encounter in an undergraduate CS program proves you have the more general cognitive skills necessary to succeed in any entry-level programming job. We just don't trust the university to say that you've done the projects and sat the exams and demonstrated competence (what it's doing when it issues a degree), so each company unwraps that abstraction and runs its own projects and exams on the same material. But it is fundamentally based on college curricula. Trusting universities is likely out of the question. Eventually, I expect the industry will create something like the Bar Exam so each candidate can pass a trusted test once upon graduation (or even without going to college), rather than creating the burden for each company to do all that grading.

notyourloops 10y ago

The last interview I went on was almost an entire work day full of computer science and programming questions, with a break for lunch.

bogomipz 10y ago
That sounds pretty horrible, could you share what company this was?
- objclxt 10y ago
  A full day of those kind of questions is pretty much the standard for the usual suspects (FB, Apple, Google, etc). Sometimes you might get a more generic design question thrown in.
  - stevenwoo 10y ago
    I interviewed at Apple a few years ago and was not asked the whiteboard programming questions (that I got asked at Google/Netflix/every game company) for a programming position.
- notyourloops 10y ago
  I don't want to share the name, but it wasn't a typical tech giant, and the position was advertised as closer to entry-level as far as programming experience went. Toward the end of the day, the last interviewer grilled me hard and I cracked under the pressure. It actually had been going well until the last two interviews (out of 5 or 6), in which one person asked me an unreasonably challenging problem (definitely not feasible for a whiteboard) and the other was not pleasant to interact with (almost confrontational the whole time; I felt on the defensive). Prior to those, it was a healthy balance of reasonable challenge and solid conversation with engineers. It seemed like a cool place to work but their interviewing arrangement was brutal. I hope not to repeat that when I go looking again.
deleted 10y ago
[deleted]

Jach 10y ago

Like another commenter I think pretty much anything after DFS/BFS is asking a bit much during a normal interview. Floyd-Warshall? I guess it might be doable if you have a mathematical description handy, I've only implemented it once for a school assignment and don't remember how long it took but it's not something I'd ask or expect to be asked... I sometimes get asked to do interviews, I'm always torn by a desire to shake things up with the broken interview process but also somewhat conform to management expectations and feedback I can give like "was able to solve Arbitrary Parts of Arbitrary Programming Challenge X." In phone screens I spend ~10 mins on data structures, I'll ask some graph representation questions if they seem like they don't have an issue with others. In longer settings (at least an hour) and especially if I know other interviewers are asking other things I'll ask them to solve a problem and actually write code on a computer. A problem I sort of like is https://leetcode.com/problems/jump-game/#/description https://leetcode.com/problems/jump-game/#/description While I think there's a pretty simple solution that just loops over every element, what I did when I tried solving it myself was recognize it's a search problem and apply the generic search algorithm to it. (Create a frontier list with an initial starting point. Create a seen/visited set. While the list isn't empty, pop an item off. If it's what you're looking for, you're done. Mark it seen, expand its children and for each one add it to the frontier list if it hasn't already been seen.) Knowing the generic (iterative) algorithm is to me more important than the particulars of DFS/BFS (you can control which one by choice of data structure), I just want to visit all reachable nodes in my search space and it works. Of the several people I've given this to only one has solved it, and by solve I mean had any right approach even if non-compiling/terrible code. (They ended up using a BFS approach.) They also are a promotion level above mine and have had more years of experience. So maybe I need to retire it, but I still like the idea of seeing if someone can recognize a search problem and solve it because there are usually many ways of solving search problems.