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 289 / 306 1200
Tree coloring 2 243 / 245 1200
Maximum sum path 200 / 234 1300
Path with length k 193 / 202 1300
Subgraph 154 / 166 1300
Beautiful tree 140 / 143 1500
Company 99 / 108 1700
Zero tree 87 / 99 1700
Selfie 30 / 37 1800