I had never even heard of HackerRank before applying at a few places. I was supposed to write a binary search tree algorithm without using anything except the language docs. I rarely write anything new without a quick search, it wastes valuable time reinventing the wheel.
I find I often forget basic language syntax when I don't have adjoining lines to crib from, say, when white boarding. And that's with languages I'm actively working in—I'm hopeless in anything I haven't used in a couple months, even if I wrote in it daily for the five years before that. I'll flat out forget which language features it supports, or how to address them.
Same. 25 years experience. (especially now that I have about a dozen obsolete languages under my belt). This is fine in daily practice, and does not interfere with productivity. But getting through that hiring filter; devastating.
I hope that this is because I have, over the years, become like Liezi's good judge of horses[1], but fear it's just that I have a bad memory for programming language details. Probably it's a bit of both.
I had a really good tech interview a while back, where I had to reverse a string in place, and then reverse only the words in a string in place (so "this is a test" => "siht si a tset")
Anyway, I had a couple of off by errors. The interviewer asked me if I was sure I didn't have any, so I had a look through, stepped through the code, and lo and behold, I did. While I was doing this process, we ended up having a discussion about how unit testing would help avoid problems like off by 1 errors, and would make iterating through the code and refactoring a lot easier.
That's what a good tech interview should look like, not expecting someone to write perfect code, first time.
On a side note, I didn't end up getting the job, since they had apparently hired someone the day before I came in for the interview. Apparently I managed to apply for the job the day they closed applications, but they asked if I wanted to interview anyway, out of courtesy.
