Ask HN: I've been a programmer for 6 years, and I can't solve basic CS problems

If you’re a bog standard “dark matter developer” using high level languages or writing your typical SAAS app, you wouldn’t need it.

I turned down a job offer where the interviewer was more concerned about whether I could write a merge sort on the board (I did), than whether I could design a system. It told me a lot about the kind of people they hire.

I spent my first 12 years as a developer doing a lot of bit twiddling in C writing cross platform code with nothing but the standard library, but these days if someone asked me how to sort I would call a library function. Heck even C has a built in sort function.

Nowhere near it - and neither do most other developers in the US.

I don't think it's really just you. Most academia seems to have a hyper-focus on algorithms and data structures. I don't know what kind of jobs they're expecting people to apply for - I'm not writing an implementation of the C++ STL, and I'd argue most of the time it's a mistake to write your own data structures with such a great ecosystem of existing implementations.

Don't get me wrong. It's great to know how binary search works, or to understand algorithmic complexity - those things come in handy. But you probably don't need to know how to find the largest palindrome in a string and you almost definitely shouldn't be writing your own hashmaps in real world code. Most people would benefit a lot more from domain specific knowledge. How do system calls work? What's a load balancer? etc, etc. Even being domain specific, a lot of the ideas can be applied outside of the context it was created in, and so knowing these things is incredibly useful.

Thankfully, most of the interviews I've had have focused a lot more on real-world situations and topics. Maybe academia will some day catch up and at least balance the focus out a bit.

A modern application developer should be at least vaguely familiar with Unicode, so character encodings should not be an entirely foreign concept.

You should be able to use a search engine to figure out what ASCII is, though. That's fair game to expect. The text document mentions ASCII, so it's not like a developer would be left without a clue.

I've had two successful exits since the early 2000's, most recently one that of a company that I built, wrote the product for and sold to a company in 2014 (all modern web based stacks, technologies etc). The last one, I ran engineering which had 25 developers and we shipped a brand new product to market and I helped sell that company (the company that bought me out) to a larger company. All the while, still writing code, building product, etc.

I had a three year earn out, finished that and decided to get back into the workforce and get a job at a senior or above level (thinking Director, Manager, etc). Guess what, not only did my age hinder me (I'm 53), but my lack of CS math background seemed too in an interview process. Various interviews had me solving what I consider not only impractical, but almost silly puzzles / math problems that not only didn't apply to the company I was interviewing with, but didn't apply to anything real-world -- it felt like it was a way to:

- Weed me out because of my age - Make the company seem like their vetting process was "Google like" and "trendy" - Make the interviewer feel entitled or the company be "elite" in their process

Part of me realizes that some of this is to see how well someone problem solves. I get that. However, I had one interviewee actually bungle up the questions, in fact, I had to point out at one point that it appeared that they described the problem wrong. When I got my answer wrong, and then asked for the answer, the interviewee clearly realized he setup the whole problem incorrectly.

Oddly enough, this is the part that bothers me the most. I've been asked many times for my GitHub. I have lots of solid examples to see my work. I've also been asked to do a programming challenge, which almost always I nail 100%. But it's always these "trap" CS challenges that I feel are used to eliminate someone based on either HOW they solve it or a way to justify them out and not hire them based on other factors (age, fit, etc.)

I actually had one that was a whiteboard session where the CTO asked me to solve the problem on the board "using code of your choice", so I stated, "Look, since I know multiple languages, I'll use pseudo code to walk through the problem and explain the answer"

When he described what he wanted me to solve (badly I might add), I wrote the pseudo-code on the board and described the problem as being solved by using regression. Which was 100% the right answer but because I chose to use pseudo-code not say, Python or JavaScript -- he told the recruiter, "he couldn't solve the problem I was looking for him to solve." When pressed by the recruiter about the solution, he gave a link to the problem in his Github, which of course was verbatim of what I described but in Python -- using regression.

What I've learned from this is that I should contract and consult. Most of these smaller companies want what they want in the way of an employee and are seeking the 10X developer, culture fit and someone in their own age group...