Duolingo Software Engineer tree traversal and graph coding assessment

After a conversation with a recruiter, I did a technical screening focused on a coding problem that felt very "standard" for interviews, something like a tree traversal. There was also a short follow-up about how I would improve the algorithm's efficiency. The interviewer kept the conversation moving. Although the core question wasn't unfamiliar, the optimization questions made me slow down and think more carefully about complexity.

A little later, I faced a more difficult assessment that turned out to be decisive. It was an online coding assignment with multiple questions and a lot of emphasis on graph-traversal-style logic. I got tripped up by hidden tests for one of the tasks, and that kept me from advancing.

Overall, the process felt straightforward but very score-driven. If the hidden cases didn't go my way, it didn't matter how well I understood the approach.

Location: New York, NY. Overall feedback: Positive. Offer status: No offer.