Software Engineer · Phone Screen · Coding

Perplexity — Software Engineer ❌ Failed

Level: Senior-Level

Round: Phone Screen · Type: Coding · Difficulty: 6/10 · Duration: 60 min · Interviewer: Neutral

Topics: Data Structures, Algorithms, Python

Location: San Francisco Bay Area

Interview date: 2026-01-15

Got offer: False

Summary

I had a coding round after the recruiter screen. The task was to implement a to-do list for AI, focusing on task dependencies.

Details

The coding round question was to implement a to-do list for AI. There were four parts, but I only finished the first two due to time constraints. The second part was particularly challenging because each task needed to record parent and child dependencies. I had to write a cascade failure helper method, which would mark all dependent tasks as failed if a task failed. I implemented a DFS solution, and it passed all test cases except for one large test case that timed out. I couldn't fix it before the end of the interview. The test cases were in a separate Python file, but I was too nervous to read and understand how the test case was structured. It might have involved hundreds of mutually dependent tasks. The format was similar to an Online Assessment, with lengthy instructions and individual test cases for each part. The interviewer immediately started the problem without any introductions. I suspect they know that most candidates can't finish the entire problem.