- Clear the boilerplate that `mix` generated
- Consume `Math.factor` to test which inputs are semiprimes
- Cache all inputs that are semiprimes as soon as we discover that they are
- semiprimes
I considered a couple things related to the Cache:
- Could save space by storing all semiprime factors in a tree. This would make
the lookups more expensive. Also because the tree's depth would never exceed
two (because all semiprimes only have two factors), the tree would be quite
broad, and we may not be saving enough space for the trade to be worthwhile. I
might be wrong about that though.
- We could consider pre-computing all semiprimes when we start the app, but
without running some tests firsts, I'm not sure whether or not it's worth the
trouble.
Define a simple in-memory key-value store for our cache.
TL;DR:
- Define `Cache` as a simple state-keeping `Agent`
- Define `Sup`, which starts our Cache process
- Define `App`, which starts our Supervisor process
- Whitelist `App` in `mix.exs`, so that it starts after calling `iex -S mix`
