- [Rust solutions from
GeekingFrog](https://geekingfrog.com/blog/post/advent-of-code-2021-1s)

## Day 13
I use an `std.AutoArrayHashMap` for storing the point on the map, it is a bit
faster to iterate through than `std.AutoHashMap`. Nothing special.
## Day 14
I store how often a given character pair appears in a `std.StringHashMap`. In
every step I just create a new map based on the previous one.
The second part takes ~15ms, this could be improved.