yairchu@gmail.com wrote:
Hi, I am pleased to announce the release of ListTree. ListTree is a package for combinatorial search and pruning of trees, and should be useful for problems such as those in Google Code Jam (where I, and possibly others* could make use of it), but possibly could even be useful for real applications! [...] One problem with my package (which I'll attempt fixing), however, is speed. I haven't used it during the competition, and the quick and dirty, less modular code, that I coded in the competition, which performs exactly the same algorithm, runs a 100 times faster! Both are fast enough, but this is still troubling. I guess I should look into "Stream Fusion" to try and make my package faster.
Have you seen Andrew Tolmach & Thomas Nordin's "Modular Lazy Search for Constraint Satisfaction Problems"? They describe a very similar project which incorporates many of the common optimizations in the field (backjumping, backmarking, forward-checking, fail-first,...) and provide their code as well. paper: http://web.cecs.pdx.edu/~apt/jfp01.ps code: http://web.cecs.pdx.edu/~apt/CSP_jfp.hs -- Live well, ~wren