[isb]

Algorithmic interview questions should ideally have multiple solutions of varying complexity. The "brute force" solution should be obvious to anyone competent enough. If they are able to code it up with reasonable clarity and test cases, that is a good start (think of it as the fizzbuzz level). Good candidates should be able to get to the "ideal/aha" solution with some hints. In fact, that process reveals a lot about the candidate. If the candidate doesn't "get" to the ideal solution on their own, it shouldn't be held against them IMO.