There's another category (possibly a subset of 1), the implementation is novel but set of requirements is known and has a set of conformance tests so tight that the LLM can basically brute force its way to a solution. See e.g. the Claude Compiler thing. In this case it's less "search engine + translator" and more of "brute force search".
How is a C compiler novel? There are so many open source C compilers. If you can download a bunch of different open source projects and they all work then it is not a novel problem, it is as solved as you can get already.
