Module DP on tree

DP on tree

**Frequency: 6/10** DP, but on tree.

Resources

- [USACO: DP on trees](https://usaco.guide/gold/dp-trees?lang=cpp)

Problems

Tree coloring 256 / 269 1200
Tree coloring 2 215 / 218 1200
Maximum sum path 179 / 207 1300
Path with length k 172 / 179 1300
Subgraph 139 / 152 1300
Beautiful tree 123 / 126 1500
Company 88 / 96 1700
Zero tree 78 / 87 1700
Selfie 21 / 25 1800