Some problems have very easy and simple solutions when using brute force methods or even basic recursive or DP solutions. What am I getting at? I was chilling solving problems and ran into this one marked as easy:

https://leetcode.com/problems/sum-of-all-odd-length-subarrays/

I was bamboozled by the difficutly system. The problem is an easy problem but a good solution requires insight and makes this trivial problem a bit more complex because it requires deeper insight and deeper mathematical analysis. The difficutly kinda made it feel like the problem is too basic. I got fooled a bit by the rating and it was a huge spoiler for me finding it out in discussion rather than being pushed to find it myself.

I would like problems such as these to have a variable difficutly like easy-medium or something like that. Basically it means a better worst case time bound complexity algorithm must exist or exists and pushes us to find it before finding this out in disucssion for a problem. Like if a problem said it can potentially be a medium problem I would look harder for a more clever solution.

Basically in another way, specificy best known time complexities in the hints or something or right next to difficulty so we can try finding them. I know some problems actually put restrictions, but I would like to know of the possibilities even if it is optional.

Even Stanford ranked this problem as difficult just because of the technique used for anaylsis.