Python coding interview challenges

Why should I ever write a merge sort when there are libraries for that? What if I have a better understanding of some other aspect of your system that you fail to identify and which your team is sorely lacking?

Not all programmers are good explainers. Someone who speaks English as a second language might have difficulty articulating the differences between two terms despite being able to code circles around you.

One of the best programmers I know explained Object Oriented Programming as "Imagine everything is a thing".

sum([5,6]) ?

> Why would I be expected to write a merge sort when there are libraries for that? That's silly.

Definitely, work samples are better, for sure and there are other puzzles on there that are probably more appropriate for a simple challenge.

In practice I'd almost never expect you to implement a sorting algorithm and I'd probably bitch in code review if you did. However, on rare occasion for optimization you may need to - if you can't implement mergesort when you are given the algorithm and offered assistance in understanding it that probably reflects poorly on your ability to implement other things too and maybe to implement in general.

> Maybe I have a better understanding of some other aspect of your system than your team does but your questions will almost definitely fail to identify that.

Maybe you do, and of course you ask these kinds of questions too, work samples should be a main focus, but I immediately get worried if someone can't solve a basic problem and can't discuss programming using shared terminology - it makes discussing these things quite difficult.

> Likewise, one of the best programmers I know once defined Object Oriented Programming as "Imagine everything was a thing". And someone who speaks English as a second language might have difficult articulating the differences between two terms despite being able to code circles around you.

I'm not expecting a specific perfect answer, just a basic answer in the right direction for a question like that. "Imagine everything was a thing" is in that direction, I'd inquire more of course, but that's a good start. As long as you have a useful understanding so that we can have a discussion that's good enough.

I see these challenges as a great way for excellent experienced developers to weed out incompetent companies.

I'm a kick-ass get-things-done full-stack web engineer. I've never had to deal with one of these sorts of problems in my day to day work; and if I did, I'd just find an existing, tested, stable library that already handled them.

A company that needs someone to solve these sorts of problems doesn't want me on their team in the first place, nor would I thrive there. A company that just needs to build damn good web apps is losing out by using these sorts of questions in their interviews.

The best interview challenge I've had (actually, it was a take-home, with discussion in the interview proper) was about designing code for re-use and extension. It was a great indicator of the company's practical and mature approach to engineering, and of what they really wanted this hire to accomplish.

I completely agree - that's why I encourage only sticking to basic questions and accepting fairly vague answers as long as they're in the right direction. Maybe your python knowledge isn't perfect, but you know how to solve it in another language. I'm good with that. Maybe you don't know the exact name of a data structure in the python standard library, as long as you can describe what you're looking for I'll point you in the right direction.

The people who don't know when to use a hashmap instead of a list of structs are the ones who concern me. So are the ones who just can't get started at all.

Sure, platforms change, languages change, but basic data structures don't, and basic OOP doesn't either. You've probably worked with many of the same data structures on many of those platforms and have a working understanding of OOP that you can describe - maybe not perfectly, but well enough.