The hashing optimization isn't necessary as using String at all is wasteful - my code ended up being simpler, but in the end the largest gain came from replacin

The hashing optimization isn't necessary as using String at all is wasteful - my code ended up being simpler, but in the end the largest gain came from replacing u64 with u32 - see https://news.ycombinator.com/item?id=11290955 https://news.ycombinator.com/item?id=11290955.