Stronger Lempel-Ziv Based Compressed Text Indexing
نویسندگان
چکیده
منابع مشابه
Indexing Text Using the Ziv-Lempel Trie
Let a text of u characters over an alphabet of size be compressible to n symbols by the LZ78 or LZW algorithm. We show that it is possible to build a data structure based on the Ziv-Lempel trie that takes 4n log 2 n(1 + o(1)) bits of space and reports the R occurrences of a pattern of length m in worst case time O(m 2 log(mm) + (m + R) log n).
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Given a string S, the compressed indexing problem is to preprocess S into a compressed representation that supports fast substring queries. The goal is to use little space relative to the compressed size of S while supporting fast queries. We present a compressed index based on the Lempel–Ziv 1977 compression scheme. We obtain the following time-space trade-offs: For constant-sized alphabets (i...
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Let a text of u characters over an alphabet of size be compressible to n symbols by the LZ78 or LZW algorithm. We show that it is possible to build a data structure based on the Ziv-Lempel trie that takes 4n log 2 n(1 + o(1)) bits of space and reports the R occurrences of a pattern of length m in worst case time O(m 2 log(mm) + (m + R) log n).
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We present a Boyer-Moore approach to string matching over LZ78 and LZW compressed text. The key idea is that, despite that we cannot exactly choose which text characters to inspect, we can still use the characters explicitly represented in those formats to shift the pattern in the text. We present a basic approach and more advanced ones. Despite that the theoretical average complexity does not ...
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A compressed full-text self-index is a data structure that replaces a text and in addition gives indexed access to it, while taking space proportional to the compressed text size. This is very important nowadays, since one can accommodate the index of very large texts entirely in main memory, avoiding the slower access to secondary storage. In particular, the LZ-index [G. Navarro, Journal of Di...
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ژورنال
عنوان ژورنال: Algorithmica
سال: 2010
ISSN: 0178-4617,1432-0541
DOI: 10.1007/s00453-010-9443-8