On Sep 28, 2012, at 3:15 PM, Darren Grant wrote:
I've been looking into memoization techniques for Haskell and am currently trying different approaches. The version below is my current attempt, a no-go right off the bat because of the dense fromList domain. However, the simplicity of the expressions is nice. Is there an elegant mechanism that can replace the fromList comprehension that will only process exactly the values requested? It seems a bit much to ask, and I'm beginning to suspect that imperative approaches are better for solving this particular memo problem.
Have you looked at http://www.haskell.org/haskellwiki/Euler_problems/11_to_20#Problem_14? The page is full of interesting and fast solutions once you have worked out your own versions.