Wow, the code is written in CWEB, a literate programming system. You don't see that every day. The PDFs of the code are, from my brief scan over them, a really well-presented explanation of some seriously deep/mathematical code.
When I heard that the solution came from using 52 CPU-years of processing, I guessed that the code was a relatively boring brute-force search. But it appears I couldn't have been more wrong about that.
When I heard that the solution came from using 52 CPU-years of processing, I guessed that the code was a relatively boring brute-force search. But it appears I couldn't have been more wrong about that.