Module Euler tour

Euler tour

**Frequency: 7/10** Also known as DFS order. This is important for solving tree related problems from now on.

Resources

- [USACO: Euler Tour](https://usaco.guide/gold/tree-euler)

Problems

Subtree queries 251 / 255 1200
Subtree update 243 / 247 1400
Ancestor 216 / 218 1400
Shallow 196 / 200 1500
Remove subtree 130 / 167 1600
Queries on tree 98 / 147 1900
Queries on tree 2 68 / 76 1900
Library 45 / 55 1900
Black vertices 40 / 44 2000