What's your straightforward recursive solution? It might be what's considered Tree DP. If you want a harder problem I can give an example too :^)

Might you have some good resources you could share then on DP strategies and problem solving? Cheers.

I did make some slides here for my university's ICPC seminar: http://www.cs.cornell.edu/courses/cs5199/2019sp/

https://docs.google.com/presentation/d/1c1YUdhXOCLSVhH6Jn4TB...

It's partially targeted for competitive programming, though, so be warned that things like Tree DP/subset DP/convex hull optimization will likely not show up in interview questions (although they are pretty cool!)