Two algorithms for approximate string matching in static texts

Abstract

The problem of finding all approximate occurrences P′ of a pattern string P in a text string T such that the edit distance between P and P′ is ≤k is considered. We concentrate on a scheme in which T is first preprocessed to make the subsequent searches with different P fast. Two preprocessing methods and the corresponding search algorithms are described. The first is based suffix automata and is applicable for edit distances with general edit operation costs. The second is a special design for unit cost edit distance and is based on q-gram lists. The preprocessing needs in both cases time and space O(|T|). The search algorithms run in the worst case in time O(|P‖T|) or O(k|T|), and in the best case in time O(|P|).