Couchbase interview questions

it had 3 technical rounds and a HR round, i was able to clear till the 2nd technical round and got to know about remaining rounds from my friends, first round of technical interview was pretty much based on DSA, it was about 1hr and i was able to solve the question and its follow ups, then in the 2nd round i was asked to show the architecture of one of my projects in my which i mentioned in the resume, and then i was asked to implement LRU caching ..i was almost there on the edge of solving but missed the edge cases and that would made me disqualify from the interview process

First round was 1 easy DSA question and resume based, second and third round dwelled more into medium difficulty DSA and a little bit of cn os. Depending on your interviewer they can also ask to include concurrency in your solution and implement multi threading