I've always considered an LRU cache question to be pretty decent. The general idea is fairly obvious (linked list + hash table) and straightforward to get somet

I've always considered an LRU cache question to be pretty decent. The general idea is fairly obvious (linked list + hash table) and straightforward to get something working and is a good indicator on how someone can synthesize data structures to fit the needs of the problem. Plus there is a lot of open endedness that makes it easy to drill down into someone's thought process.