I love his hash table solution to level0!
I would never have spent much time optimizing such a trivial challenge as level0, but after seeing the leaderboards with such ridiculous scores, curiosity got the best of me, and I had to figure out how people were achieving such speedups.
I used a precomputed bloom filter to get 2641 points on level0, because I couldn't think of another way to avoid doing the expensive processing of the dictionary ahead of time. That solution simply read in the filter from a file at run-time. I thought of embedding the data in the source code to avoid the file I/O, but instead moved on to work on some of the later levels.