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 364 / 383 1200
Tree coloring 2 312 / 315 1200
Maximum sum path 261 / 298 1300
Path with length k 256 / 264 1300
Subgraph 208 / 218 1300
Beautiful tree 180 / 186 1500
Company 144 / 151 1700
Zero tree 118 / 132 1700
Selfie 57 / 74 1800