The is simply just "Longest Path in a DAG" as others mentioned. However, the technique you're using is actually topological sorting with dynamic programming .
Make sure you mention DAG. Finding a longest path in general graphs is NP-Complete.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.