I was introduced to Kattis in a second year computer science class where we were using prescribed problems for assignments and midterm exams. It was really enjoyable to have these problems encorporated into the curriculum, and I still years later like to do occasional problems to keep improving my coding skills.
Most solutions are in Java as that was used in my second year class, but I have started doing some in Python as well.
I hope these solutions can help some people out if they are stuck doing them for a class! Just remember not to copy-paste since you will probably get caught by your prof!