Document Type

Article

Publication Date

7-1-2011

Abstract

This paper revisits the problem of indexing a text for approximate string matching. Specifically, given a text T of length n and a positive integer k, we want to construct an index of T such that for any input pattern P, we can find all its k-error matches in T efficiently. This problem is well-studied in the internal-memory setting. Here, we extend some of these recent results to external-memory solutions, which are also cache-oblivious. Our first index occupies O((nlogkn)B) disk pages and finds all k-error matches with O((|P|+occ)B+logknloglogBn) I/Os, where B denotes the number of words in a disk page. To the best of our knowledge, this index is the first external-memory data structure that does not require Ω (|P|+occ+poly(logn)) I/Os. The second index reduces the space to O((nlogn)B) disk pages, and the I/O complexity is O((|P|+occ)B+logk(k+1)nloglogn) . © 2011 Elsevier B.V. All rights reserved.

Publication Source (Journal or Book title)

Theoretical Computer Science

First Page

3579

Last Page

3588

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