Holy moly, I thought I was the only one!

"Want me to write a specialised API with custom encapsulation transmitted over UDP?"

"Nah fam, we want to watch you code in our super-duper-wiz-bangy-exclusive IDE that you've never used before. Oh, and you have an hour. Oh, and it's going to be super-specific tasks that only we know how to do."

"So, no on the encapsulation, eh?"

<click>

This must be common, I just bombed a leetcode (tm) interview where I was asked to write code to share a method between two structs using traits in Rust without duplicating code. I couldn't remember a time I'd ever seen it done with generics so I tried to find it in the documentation but nothing. I looked up the solution after and it is not possible without writing a macro which is metaprogramming and seems like a poor way to assess how I'd perform writing Rust on a daily basis when I only had ~20 minutes to do it and was transparent that I am still learning the more advanced concepts. There were other red flags I ignored in the interview process, I look at it as a bullet dodged.

The real answer here is take whatever the R data.table package is doing and copy that. It's even written in C. It's by far the best csv reading package I've ever used and will sort as it reads, sometimes extremely fast since it can pretty intelligently guess if a radix sort is possible. The only downside is I believe it can only handle csvs that fit in memory, but memory is getting pretty damn big these days. I used it as inspiration a long while back when I needed to write a library to read in ARPA-formatted n-gram language models, which is a fairly obscure file format I could not find any existing libraries for.

Of course, data.table has existed for over a decade and you're not going to come up with something comparable in 15 minutes, but that's why you'd want to just copy it and not come up with your own solution in the first place.

Likewise. I've known C since the 90s, C++ since the 00s (with a refresher for C++11), and recently picked up Rust—have already written a few thousand lines, it's a great language. But I do DevOps because the pay is better and the interviews are practical.

I'd be tempted to just use sort(1) in that situation and say "what? it's in C" if questioned.

Maybe I'm missing something but unless the interviewer expects a 100% correct csv parser that handles all possible corner cases this is basically

- read file

- start at beginning; if you encounter separator, add new entry to an array. if you encounter newline, save entire current array as a new line to an array of lines.

- do lexicographical sort of arrays (can just use qsort for this).

- if the test q actually wants you to parse out numbers and shit like that, nothing about the structure changes, you just have to record some extra info when parsing values and then use a different comparison depending on the type in the function you pass to qsort

I dare say someone programming algorithms in a kernel or writing code for custom file systems should be able to do this. OK 15 min may be tight if you're nervous but you should get there.

Brother !