---
categories: Data structure techniques
---

## Problems
- [The SetStack Computer](http://www.csc.kth.se/contest/nwerc/2006/problems/nwerc06.pdf)
- [Common Subexpression Elimination](https://archive.algo.is/icpc/nwerc/2009/nwerc09.pdf) [^1]
- [Squadtrees](http://codeforces.com/gym/100228)

## See also
- [Hashing]()
- [Graph isomorphism#trees]()

[^1]: <https://archive.algo.is/icpc/nwerc/2009/solOutline.pdf>