Looks like a decent problem set to accompany an introductory ML class. No need to get so defensive. However, I thought leetcode meant algorithmic problem solving while the problems here simply ask to implement the various elementary operations.
I think as a learning tool this is pretty great! I want to implement the most common ML and stats algos over the next few months to review how they work on a deeper level and your website will help a lot. I like that you explain all terms in your equations.
Personally, I would probably enjoy even more explanations and/or links to good resources, e.g., visualizations, etc. as well as more information in the solutions (e.g., via comments or doc strings). Good job anyway!
