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Comment by rhyperior | Hacker News Reader

Exactly! I used this question regularly. It wasn’t a gotcha question or even an impossible-without-experience question as the author thinks. It was a show me HOW you think through something question. There are a lot of ways to solve it, from scanline to sin/cos to using the circle equation, but you can _progress_ from naive to advanced solutions, and all solutions above plus the DDA or Bresenham solutions have symmetries (hint: more than four quadrants are symmetrical) that you can use to optimize it. A practiced interviewer can learn a lot about the candidate with this question.

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I wonder if there's a class of people who managed to get CS degrees but really aren't that good. To them, it might feel more like either you remember the perfect and optimal but complex solution you were taught in a class, or you don't happen to remember it and are completely stuck and can't make any progress at all. I don't think I'd want to hire or work with somebody who can't come up with some sort of solution after thinking through it for a few minutes.

In fact, coming up with the CS-perfect solution immediately may be a bit of an anti-signal. I want the person who can think their way through to a solution to a problem that's new to them reasonably well. The fact that you happened to have memorized the best algorithm for this and can recite it on command doesn't tell me much useful, because nobody has the perfect algorithm for everything memorized.

> I wonder if there's a class of people who managed to get CS degrees but really aren't that good

This is a horrible over-generalization, but it seems to me that at least for last 10 years or so colleges are creating students who are more like systems integrators (glorified stack overflow cut-and-pasters) than developers who can equally well think for themselves and derive things from scratch.

I learned to program in the late 70's in the 8-bit home computer era, and developers of my generation had no choice but to write most of everything from scratch, other than implementing a few well known published algorithms. You approached everything from a perspective of "how can I solve this problem?" rather than "what can I find to solve this problem for me?". Additionally due to severe hardware constraints (speed, memory) we had to always be creative and think outside the box - the mentality was that nothing was impossible, just a matter of finding the best solution.

It's not necessarily a class of people. It's proficiency vs. mastery. Is some set of people more able to master a subject than another? Sure. Each person has different limits to their potential, of course, but for most things achieving mastery is more a matter of putting the work in over time.

A family member took the same calculus class that I did, from the same teacher. They passed, per their own account, only by memorizing the rules. I memorized what I needed to but the concepts clicked intuitively. So sure, some people “get it” and some people just pass a subject like CS.

> I wonder if there's a class of people who managed to get CS degrees but really aren't that good

Yes, yes, oh my god yes!

The classic one that will stick in my memory forever was the candidate with an MSCS who was given the problem description and categorized and described what class of problem it was, but completely failed to make any progress in solving it.

I'm sure she was great at complex algorithms, but we just wanted a for... loop to start with.

The flipside of this is that one of the best hires we ever made had such a bad resume that I remember storming into my boss' office and asking why I was wasting my time interviewing that person.

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