Jokes aside, lookup tables are a common technique to avoid costly operations. I was recently implementing one to avoid integer division. In my case I knew that the nominator and denominator were 8 bit unsigned integers, so I've replaced the division with 2 table lookups and 6 shifts and arithmetic operations [1]. The well known `libdivide` [2] does that for arbitrary 16, 32, and 64 bit integers, and it has precomputed magic numbers and lookup tables for all 16-bit integers in the same repo.

[1]: https://github.com/ashvardanian/StringZilla/blob/9f6ca3c6d3c... [2]: https://github.com/ridiculousfish/libdivide