I've been going through Nora Sandler's Writing a C Compiler book and writing a compiler in Python. I'm excited to start the chapters on optimization - those seem like the most fun algorithm problems.

I recommend the book. It certainly isn't easy (maybe 3x harder than Crafting Interpreters), but I've learned a ton (eg how to deal with operations on different sizes of types, or the trick of using pseudoregisters to avoid having to figure out registers up front).

https://github.com/jmikkola/writing-a-c-compiler-python