Asking a person to traverse and modify a linked-list (a very common problem) or to implement a B-tree are not 'tech outside their job'
Most of these interviews are more like math problems than anything a practical developer would encounter.
Shit, if these interviews were "What do you think of node?" or "What is Go's concurrency model?" I think experienced people would do fine.
No. No one in their daily jobs implements a linked list or B-Tree. There are predefined libraries in the languages or a user created library that people use. Do you really think every person in the company has his/her own version of a linked list in the same code base? This is a fallacy perpetuated time and again. (I'm not against these type of questions, but they don't represent someone's true ability)
Building a product, app, project requires application of this knowledge: eg., I need to design a distributed data store, should I use hash map? What about collisions? Should the collisions be resolved by chaining (linked List) or another map? What kind of data am I storing? Can that be exploited to make this more efficient, synchronization of data across nodes (?), etc..
Many of these interviews completely overlook someone's design ability and harp on some straightforward (and some obscure) topics which IMO has little to no co-relation to someone's ability as a software engineer.
Why is everyone stuck on getting someone to reinvent the wheel as against getting him to use the said wheel and get things done.
I find the processes in a large company rather robotic (note: we're a startup, so my views might be biased).
A person who can only use a pre-made wheel is a technician (regardless of how ostentatious their job title may be).
A person who can invent the wheel on demand can also usually invent any other type of rolling mechanism one might encounter a need for and that makes that person a full-fledged engineer.
No value judgement of either person is implied; it's simply a statement of capability. Which type of person is needed depends on the company and the position but it is becoming increasingly clear that the two roles in software are separate, just as they are in other engineering disciplines.
Counter case: HFT. Those guys really do implement this stuff. Again and again.
Yes, it is.
More to the point, it's built-in bias toward recent college graduates. Once someone's actually been out in the real world programming for several years, any space in their brain's metaphorical working set that was ever dedicated to remembering how to do this stuff has long since been paged out in favor of the actual day-to-day knowledge they need to do their job. Implementing basic data structures and algorithms is not part of what they need to do their job; that stuff's already provided by the platforms they use.
So when you get to the interview, if you just put someone on the spot and ask them to do one of these things, you're inherently biasing toward an inexperienced recent college graduate who will have this stuff close to the top of their head (on account of having just done it in school and not yet swapped it out of working memory through time on the job).
Which is in turn why there are now books you study -- as an already-qualified programmer -- in order to freshen your memory and ability to quickly regurgitate problems that have nothing whatsoever to do with your day-to-day work, in order to be able to perform them on command in interviews.
Also these days the trendy interview problem is longest common subsequence, which ends up testing "how recently did you review dynamic-programming techniques", not "can you code".
I'll be honest, this is indistinguishable from "I am good at X and I'm great therefore X is a good measure of ability".
Maybe worth rephrasing
If the point of the exercise is a TRIVIA question, leave the interview. On the other hand, if the point of the exercise is not to get the right solution but see how you think and how you use basic programming blocks, then you're in the right place.
I've used the linked list question. And the goal is not for me to check if it is "not difficult" for you. Because I might not be able to teach you what a linked list is in 5 minutes while you're nervous in a technical interview. But to work on technical problems and see the following:
- Can you speak your mind so your peers know what are you doing?
- Will you ask for help?
- Will you accept help and feedback?
- Can we have a discussion about something that there are many "right answers"?
- Do you know the basic building blocks of the language you decided to use? <-- This plus javascript plus references is very funny.
What you're describing is a confidence bias filter, dressed as an objective test.
But in practice it's merely one of hundreds of things that might get instantly sprung on you as you stand before a whiteboard. In addition, developers with actual jobs can't stay in a continuous cycle of "exam cram" to the same extent that unemployed recent graduates can.
I've never used Go, don't really plan to unless I have to, nothing wrong with it just not my area of expertise and I'm busy with other toys although I'm sure its a very nice language, and if I went up against a non-technical or technically weak interviewer (aka almost all of them) I could probably BS my way thru based on what I do know about concurrency in general. Although after decades of experience, the reason why I'm not still programming in 6502/Z80 assembler is I'm good at that whole "BS my way thru till I'm an actual expert" thing, so maybe I'm talking myself into agreeing for non obvious reason!
BSing skill is under-rated. If you can't BS your way thru something that you don't entirely understand (because you're lazy), then when you're at the cutting edge developing or debugging you'll have trouble BSing about stuff that no one on the planet understands. Not all the worlds problems have a stack overflow question or a script reader at a support hotline, and how you deal with that gut check says a lot.
(I listened to a training video given by a Marketing Cloud consultancy at my work. Someone asked "what is FTP" after seeing that as an option to upload files. Lots waffle including "the cloud" and no actual answer. The person asking the question was no wiser, and my opinion of the consultant went way down).
It is true that many managers, recruiting agencies (almost 100%), and HR, will look for the keywords of the technologies the company is using. So if they use the new Angular 4, they will look for that.
But there are companies that look for the basics: do you know javascript? Have you worked with SPAs? And these are the ones that IMHO deserve your time to apply.
Because tomorrow, today's current trends will be tomorrow's trends. Companies looking for people that can adapt say a lot about what kind of work place will you find there.
I know enough about relational databases and NoSQL to know that unless you have a specific use case, relational is likely a better choice. If you are not scaling beyond one server, and want to view your data from different angles its almost certainly a better choice. As such I haven't really got a great deal of NoSQL experience. I will build a better application than someone who does resume driven development, but won't get past many HR drones.
If you don't have a relational query in mind a relational DB is a bad fit, or at least premature optimization.
Maybe "to do the thinking for them" would be more accurate.
> sound like a good thing to me.
You did what they do - you assumed based on some your usual workloads that a DB and the overhead of using another language, and a non-compile-time checked language, with poor integration (type mismatch), is the solution for the problem I'm working on.
What I expect them to do is ask questions. How many values are there? Are they complex types or something that would map to tables well? What are the querying requirements? Are there any relational elements to the data?
> Its usually way faster than doing stuff in the application code
If shoving things across two sets of pipes, to a general-purpose app not tuned to your workload, is faster - you're writing your main app incorrectly.
> the declarative nature of SQL usually means less bugs.
A declarative language usually means less bugs. But adding a second mismatched language usually means more. Especially when it comes with a whole new system that takes experts to properly tweak.
As developers get older, they need to be conscious of the relevance of their work in regards to current trends, and if the day job is largely irrelevant they may need to find access to projects (often unpaid) that will serve to impress new employers.
I don't think that the value of experience has truly diminished, but I think what is now classified as 'experience' may have shifted a bit.