Spaces, trees, and colors: The algorithmic landscape of document retrieval on sequences

G Navarro - ACM Computing Surveys (CSUR), 2014 - dl.acm.org
Document retrieval is one of the best-established information retrieval activities since
the'60s, pervading all search engines. Its aim is to obtain, from a collection of text …

[HTML][HTML] Wavelet trees for all

G Navarro - Journal of Discrete Algorithms, 2014 - Elsevier
The wavelet tree is a versatile data structure that serves a number of purposes, from string
processing to computational geometry. It can be regarded as a device that represents a …

Alphabet-independent compressed text indexing

D Belazzougui, G Navarro - ACM Transactions on Algorithms (TALG), 2014 - dl.acm.org
Self-indexes are able to represent a text asymptotically within the information-theoretic lower
bound under the k th order entropy model and offer access to any text substring and indexed …

The wavelet matrix: An efficient wavelet tree for large alphabets

F Claude, G Navarro, A Ordónez - Information Systems, 2015 - Elsevier
The wavelet tree is a flexible data structure that permits representing sequences S [1, n] of
symbols over an alphabet of size σ, within compressed space and supporting a wide range …

Improved grammar-based compressed indexes

F Claude, G Navarro - International Symposium on String Processing and …, 2012 - Springer
We introduce the first grammar-compressed representation of a sequence that supports
searches in time that depends only logarithmically on the size of the grammar. Given a text T …

Optimal dynamic sequence representations

G Navarro, Y Nekrich - SIAM Journal on Computing, 2014 - SIAM
We describe a data structure that supports access, rank, and select queries, as well as
symbol insertions and deletions, on a string S 1, n over alphabet 1..σ in time …

Compact querieable representations of raster data

G De Bernardo, S Álvarez-García, NR Brisaboa… - String Processing and …, 2013 - Springer
Abstract In Geographic Information Systems (GIS) the attributes of the space (altitude,
temperature, etc.) are usually represented using a raster model. There are no compact …

Colored range queries and document retrieval

T Gagie, J Kärkkäinen, G Navarro, SJ Puglisi - Theoretical Computer …, 2013 - Elsevier
Colored range queries are a well-studied topic in computational geometry and database
research that, in the past decade, have found exciting applications in information retrieval. In …

Lightweight lempel-ziv parsing

J Kärkkäinen, D Kempa, SJ Puglisi - International Symposium on …, 2013 - Springer
We introduce a new approach to LZ77 factorization that uses \O(n/d) words of working space
and \O(dn) time for any d≥ 1 (for polylogarithmic alphabet sizes). We also describe carefully …

[HTML][HTML] On compressing permutations and adaptive sorting

J Barbay, G Navarro - Theoretical Computer Science, 2013 - Elsevier
We prove that, given a permutation π over [1.. n] formed of nRuns sorted blocks of sizes
given by the vector R=< r 1,…, r nRuns>, there exists a compressed data structure encoding …