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I'm looking for a (space) efficient implementation of an LCS algorithm for use in a C++ program. Inputs are two random access sequences of integers.
I'm currently using the dynamic programming approach from the wikipedia page about LCS. However, that has O(mn) behaviour in memory and time and dies on me with out of memory errors for larger inputs.
I have read about Hirschberg's algorithm, which improves memory usage considerably, Hunt-Szymanski and Masek and Paterson. Since it isn't trivial to implement these I'd prefer to try them on my data with an existing implementation. Does anyone know of such a library? I'd imagine since text diff tools are pretty common, there ought to be some open source libraries around?

+1  A: 

When searching for things like that, try scholar.google.com. It is much better for finding scholarly works. It turned up http://www.biotec.icb.ufmg.br/cabi/artigos/seminarios2/subsequence_algorithm.pdf this document, a "survey of longest common subsequences algorithms".

Lagerbaer
Grudging +1 because the OP really wants library implementations of said algorithms, not descriptions. But probably a useful paper anyway.
j_random_hacker
j_random_hacker