Are there any other such data structures besides arrays and hash tables? (That's only half-rhetorical. I'd love to hear about one.) If so, are you seriously sug

Are there any other such data structures besides arrays and hash tables? (That's only half-rhetorical. I'd love to hear about one.) If so, are you seriously suggesting that when an array fits the bill, we should stop and think "hmm... maybe another data structure would be a better container for this dense, contiguous set of integer keys"?