Their definition of an LRU cache didn’t even include a key. What’s the point of a cache if you can’t fetch a value by key? The test cases were just as flawed. In a proper LRU cache, the most recently accessed item moves to the front, and the least recently used one gets evicted when capacity is full. Their tests didn’t reflect this at all. To make things worse, they sent a non-technical program manager to conduct a coding interview. He clearly didn’t understand what an LRU cache is. He kicked off the interview, then disappeared. When I pointed out the flaws in their test cases, he started arguing instead of listening. Very unprofessional.