Approximately Matching Context - Free
نویسنده
چکیده
Given a string w and a pattern p, approximate pattern matching merges traditional sequence comparison and pattern matching by asking for the minimum diierence between w and a string exactly matched by p. We give an O(PN 2 (N + logP)) algorithm for approximately matching a string of length N and a context-free language speciied by a grammar of size P. The algorithm generalizes the Cocke-Younger-Kasami algorithm for determining membership in a context-free language. We further sketch an O(P 5 N 8 8 P) algorithm for the problem where gap costs are concave and pose two open problems for such general comparison cost models.
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