25 July 2013

A couple of people had asked how the story with the company that triggered the "I Hate Programming Tests" post ended, so I figured I'd follow up with the rest of that story, and some thoughts.

After handing in the disjoint-set solution I'd come up with, the VP pondered things for a bit, then decided to bring me in for an in-person interview loop with a half-dozen of the others that work there. I said I'd be happy to, and came in, did a brief meet-and-greet with the group of folks I'd be interviewing with (plus, I think, a few others), and then we got to the first interview mono-a-mono, and after a brief "Are you familiar with MVC?", we get into...

... another algorithm challenge. A walk-up-to-the-whiteboard-and-code-this challenge.

OK, whatever. I already said I'm not great with algorithmic challenges like this, but maybe this guy didn't get the memo or he's just trying to see how I reason things through. So, sure, let's attack this, even though I haven't done this kind of problem in like twenty years. (One of the challenges was "How do you sort a file of integer numbers when you can't store the entire collection of numbers in memory?", which wasn't an unfair challenge, just not something that I generally have to mess with. Honestly, in the working world, I'll start by going through the file number by number--or do chunks of the file in parallel using actors, if the file is large enough--and shove them into a database that's indexed on that number. But, of course, as with all of these kinds of challenges, the interviewer continues to throw constraints at the problem until we either get to the solution he wants or Ted runs out of imagination; in this case, I think it was the latter.) End result: not a positive win.

Next interviewer walks in, he wasn't there for the meet-and-greet, which means he has even less context about me than the guy before me, and he immediately asks... another algorithmic challenge. "If you have a tree of nodes, and you want to get a list of the nodes in rank order" (meaning, a breadth-first search, where each node now gets a "sibling" pointer pointing to the sibling on its right in the tree, or null if it's the rightmost node at that depth level) "how would you do it?" Again, a fail, and now I'm getting annoyed. I admitted, from the outset, that this is not the kind of stuff I'm good at. We've already made that point. I accept the "F" on that part of my report card. What's even more annoying, the interviewer keeps sighing and drumming his fingers in an obvious state of "Why is this bozo wasting my time like this, I could be doing something vastly more important" and so on, which, gotta say, was kind of distracting. End result: total fail.

By this point, I'm really annoyed. The VP comes to meet me, asks how it's going, and I tell him, flatly, "Sucks." He nods, says, yeah, we're going to kill the interview loop early, but I want to talk to you over lunch (with another employee along for company) and then have you meet with one more person before we end the exercise.

Lunch goes quite well, actually, and the last interview of the day is with their Product Manager, who then presents me with a challenge: "Suppose I want to build an online system for ordering pizzas. Customers can order pizzas, in other words. Build for me either the UI or the data model for this system." OK, this is different. I choose the data model, and build a ridiculously simple one-to-many relationship of customers to orders, and a similar one-to-many for orders to pizzas. She then proceeds to complicate the model step by step, sometimes in response to my questions, sometimes out of the blue, until we have a fairly complex roughly-sketched data model on the whiteboard. Result: win.

The VP at this point is on the horns of a dilemma: two of the engineers in the interview loop are convinced I'm an idiot. They're clearly voting no on this. But he's read my articles, he's seen some of my presentations, he knows I'm not the idiot the others assume me to be, and he's now trying to figure out what his next steps are. He takes a week to think about it, then emails me yesterday to say that it's not going to work.

Here's my thoughts, and folks, if you interview people or are part of an interview process, I'm trying to generalize this beyond this one experience to take it into a larger context:

In the end, this is probably the best of all possible scenarios, not working for them, particularly since I have some other things brewing that will likely consume all of my attention in the coming months, but there's that part of me that hates the fact that I failed at this. That same part of me is now going back through a few of the "interview challenges" books that I picked up, ironically, for my eldest son when he goes out and does his programming interviews, just to work through a few of the problems because I HATE feeling inadequate to a challenge.

And that, in turn, raises my next challenge: I want to create a website, just a static thing, that has a series of questions that, I think, are far better coding challenges than the ones I was given. I don't know when or if I'm going to get to this, but I gotta believe that any of the problems out of the book "Programming Challenges" (by Skiena and Revilla, Springer-Verlag, 2003) or the website from which those challenges were drawn, would be a much better test of the candidate's ability, particularly if you look at the ancillary parts of the challenge: do they write tests, how do they write their tests, do they pair well with somebody, and so on. THOSE are the things you really care about, not how well they remember their college lessons, which are easily accessible over Google or StackOverflow.

Bottom line: Your time is precious, people. Interview well, or just don't bother.

Tags: industry   development processes   languages   reading   interviewing  

Last modified 25 July 2013