Same exact thing happened to me last year. Two rounds, solved both, got the mixed feedback call, did a third, then silence. "Not strong enough" is their standard line I think.

Sorry to hear this. I've seen a lot of posts about Snowflake rejecting candidates who clearly solved the problems. Their rubric must be more than just correctness.

Two weeks of silence after the third round tells you everything. They already knew the answer and just forgot to close the loop. Frustrating but not uncommon.

Curious, did you do multi-source BFS from all cake positions simultaneously or from each person individually? Just trying to understand if there was anything that could have caused confusion.

Snowflake loop is rough. The third round ask is a red flag imo, means at least one interviewer gave you a no and they're trying to override it. Doesn't usually end well.

The inflexible interviewer on round 2 is a known thing at Snowflake. I had one too who wouldn't accept my BFS solution and just kept saying there was an issue. No counterexample, nothing.