Snowflake - 3 coding rounds and still rejected

Snowflake - 3 coding rounds and still rejected

Had two phone screens and then a surprise third round after they said feedback was mixed. Here's the breakdown.

First phone screen was the classic cake/people grid BFS. 2D array, cakes represented as 1, people as 0, find minimum distance for each person to nearest cake. Multi-source BFS from all cakes simultaneously, got O(m*n), no issues. Interviewer was pretty quiet throughout.

Second phone screen was another BFS variant on a similar grid setup, this time with bathrooms and desks. Same idea, ran through it in about 30 minutes and spent the rest talking through edge cases. Interviewer just said "okay" and ended the call.

Recruiter reached out two days later saying feedback was mixed and asked if I'd do a third round. I said sure. Third one was an event tracking system: implement Receive(event_type, timestamp) and Count(event_type, start_time, end_time). Standard hash map with sorted timestamp lists, O(log n) lookup. Thought I was clear in explaining the tradeoffs.

Rejected a week later. Feedback: "not strong enough." Three medium coding problems, solved all of them, explained my approaches. Not sure what else they wanted, honestly. Pretty demoralizing ngl.