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 268 / 283 1200
Tree coloring 2 229 / 232 1200
Maximum sum path 190 / 222 1300
Path with length k 179 / 188 1300
Subgraph 145 / 158 1300
Beautiful tree 129 / 132 1500
Company 93 / 102 1700
Zero tree 83 / 93 1700
Selfie 24 / 31 1800