The answers to a lot of these are now google-able; you’ll learn more by researching than being spoon fed the solution!
Imagine those of us students back then when google wasn’t a verb yet trying to solve these problems!
I am looking to self-study for core CS content that I missed out on in school after being largely self-taught, and courses that change the way one’s brain works sound like the right ones to take.
If you want to start with the fundamentals, CS 173 (Discrete Structures) is required of all undergrad CS majors and is the first of the sequence (usually taken as a freshman/sophomore). The book is available online along with problems/solutions: http://mfleck.cs.illinois.edu/building-blocks/index.html