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 581 / 600 1200
Tree coloring 2 499 / 505 1200
Maximum sum path 412 / 462 1300
Path with length k 381 / 391 1300
Subgraph 331 / 342 1300
Beautiful tree 288 / 296 1500
Company 226 / 233 1700
Zero tree 190 / 207 1700
Selfie 118 / 133 1800