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 226 / 239 1200
Tree coloring 2 192 / 194 1200
Maximum sum path 159 / 184 1300
Path with length k 153 / 161 1300
Subgraph 124 / 132 1300
Beautiful tree 111 / 115 1500
Company 77 / 84 1700
Zero tree 68 / 76 1700
Selfie 12 / 14 1800