Did you ever saw a char and thought: "Damn, 1 byte for a single char is pretty darn inefficient"? No? Well I did. So what I decided to do instead is to pack 5 chars, convert each char to a 2 digit integer and then concat those 5 2 digit ints together into one big unsigned int and boom, I saved 5 chars using only 4 instead of 5 bytes. The reason this works is, because one unsigned int is a ten digit long number and so I can save one char using 2 digits. In theory you could save 32 different chars using this technique (the first two digits of an unsigned int are 42 and if you dont want to account for a possible 0 in the beginning you end up with 32 chars). If you would decide to use all 10 digits you could save exactly 3 chars. Why should anyone do that? Idk. Is it way to much work to be useful? Yes. Was it funny? Yes.
Anyone whos interested in the code: Heres how I did it in C: https://pastebin.com/hDeHijX6
Yes I know, the code is probably bad, but I do not care. It was just a funny useless idea I had.
There is still fun to be had! Just... Different fun!
In database land lookup tables are pretty common. Prefix tries and the like are super common in search land. I've seen GCD, offset, delta-of-delta, and some funky bitwise floating point compression used. Sometimes just to save dist space. But usually to save working set space or IO or S3 cache space.
And squeezing the most out of modern CPUs is its own art. Compilers are glorious. And modern CPUs are magic lightning rocks. But you can learn to sing to them just right to make them all happy.