The Worst Mistake You Can Make in a Technical Interview
By: Mandi Gunningham
Tags: Startup, Interview, Software Development, Programming

Embarrassing Story Time

Now that you’ve got the idea, learn from my cringe-tastic experience!

I got lucky with my first developer job and got into the company via some solid networking. There was an interview process, but it was not an intense technical challenge. Therefore, when it came time to start looking for my next role, I was not very practiced with code screenings and technical challenges.

Early on in the process, I got an interview with a large company for a data-driven, machine learning role. It had been a few years since I graduated at that point, so my algorithmic knowledge had degraded. I started studying up on my data structures, algorithms, and all that jazz.

I aced my first two interviews, which were more personal, less technical. They comprised problem-solving and general situational questions. That is my strength — I can spin any experience into a life lesson learned. And honestly, it’s not just spin, but that’s a topic for another time. We’re talking technical today.

Finally it came time for the technical interview. This was to be my second-ever technical interview, and I expected it to be more in-depth than my first. I was nervous, to say the least!

The interview began with a code challenge. I was given lines of code that were out of order, and I had to put the lines in order to create a functioning algorithm. Not super difficult, but stressful nonetheless — it included at least one nested loop, and with no context that’s more confusing than you’d expect!

Either way, I did very well on this part. One of the interviewers even said that I did better than he had during his interview! I was feeling encouraged at that point.

Next it was time to discuss the code. It was a very simple encryption algorithm, more string manipulation than anything, so I was able to keep up. Eventually, though, we got to the dreaded question: How could we improve this code?

I floundered. I took my time to read through the code again. I made a suggestion — something about stronger encryption. Not what they were asking.

Then I made the dreaded mistake. I suggested that since there was a nested loop that it would be possible to improve the time complexity. Now, I knew something about the topic, enough to know that, generally, nested loops are not super-efficient.

However, I didn’t know enough to hold an intelligent conversation or actually suggest an improvement. The interviewer was giving me nothing. I said we could improve the time complexity, and he said, “Interesting, how?” That’s the moment where I could have gracefully backed out by stating that nested loops generally weren’t efficient (tell them what you do know), but that I didn’t have an improvement off the top of my head (no bullshit).

Probably my interviewers face as I rambled incoherently about optimizing algorithms (Photo by Andrea Piacquadio from Pexels)

Obviously, I didn’t do that, though, or this story would be very different. He was trying to ask illuminating questions and point me in the right direction, but I was officially in panic mode. We went around in a few circles before I finally tapped out. It was embarrassing, to say the least.

The interview ended pretty much at that point. I don’t even remember them asking me any more questions. I knew it was over at that point. I didn’t get the callback and finally heard from my recruiter that they were passing on me.