Sierra debugging interview

Round 4 of 6 · 5 questions reported

Length: 60 min
Format: Find and fix several bugs in a prepared TypeScript and React app
They grade: Fluency in the stack, systematic diagnosis, speed, and explaining each bug's effect on the user
AI use: Historically no AI coding tools; an AI-assisted version is being piloted, so ask

Questions Sierra asks in this round 5

Print timed text intervals in order and flag overlaps and gapsCodingYou get a list of time intervals, each with a piece of text, and print them in time order, much like merge intervals. The follow-up asks you to report where two intervals overlap…
Last asked Nov 2025
Maximum element in an arrayCodingReturn the largest element of an array in one pass. Reported on 1point3acres' Sierra bank; reconstructed in our own words.
Merge ordered streamsCodingMerge several ordered input streams into one ordered output without loading any stream fully into memory. Reported on 1point3acres' Sierra bank; reconstructed in our own words.
Multiples streamCodingGenerate the infinite stream of multiples (or Hamming-like numbers) lazily, yielding values in order on demand. Reported on 1point3acres' Sierra bank; reconstructed in our own…
Ordered integer streamCodingMaintain an integer stream that yields values in order as out-of-order inserts arrive. Reported on 1point3acres' Sierra bank; reconstructed in our own words.