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categories: Linear algebra, Combinatorics, Graph theory
---

## Problems
- [Organising the Organisation](https://open.kattis.com/problems/organising)
- [Join](http://acm.timus.ru/problem.aspx?space=1&num=1627)
- [Amazing Mazes!](https://projecteuler.net/problem=380)
- [Unicyclic Count](https://open.kattis.com/problems/unicycliccount)

## External links
- [Kirchhoff theorem. Finding the number of spanning tree](https://cp-algorithms.com/graph/kirchhoff-theorem.html)
- [Kirchhoff's theorem](https://en.wikipedia.org/wiki/Kirchhoff%27s_theorem)