I prepare for my next jobs search. I am not really sure what to expect with such questions. Some medium and hard LC questions have a good number of edge cases, that it is extremely hard to foresee if you see the problem in the first time.

I have spent like 3 hours solving LRU Cache problem to make it pass all the tests with O(1) average time complexity. I spent like half an hour coding and 2.5 hour catching and debugging all the edge cases i didn't account from the beginning. I cannot imagine to write such code that passes all the tests without IDE and debugger, especially.

Do interviewers run all tests? Or it is better focus on high level idea and make it conceptually with right approach?

I am not sure how strict to be for myself while preparing.