TY - GEN
T1 - Persistency in suffix trees with applications to string interval problems
AU - Kopelowitz, Tsvi
AU - Lewenstein, Moshe
AU - Porat, Ely
PY - 2011
Y1 - 2011
N2 - The suffix tree has proven to be an invaluable indexing data structure, which is widely used as a building block in many applications. We study the problem of making a suffix tree persistent. Specifically, consider a streamed text T where characters are prepended to the beginning of the text. The suffix tree is updated for each character prepended. We wish to allow access to any previous version of the suffix tree. While it is possible to support basic persistence for suffix trees using classical persistence techniques, some applications which can make use of this persistency cannot be solved efficiently using these techniques alone. A collection of such problems is that of queries on string intervals of the text indexed by the suffix tree. In other words, if the text T = t1...tn is indexed, one may want to answer different queries on string intervals, ti...tj , of the text. These types of problems are known as position-restricted and contain querying, reporting, rank, selection etc. Persistency can be utilized to obtain solutions for these problems on prefixes of the text, by solving these problems on previous versions of the suffix tree. However, for substrings it is not sufficient to use the standard persistency. We propose more sophisticated persistent techniques which yield solutions for position-restricted querying, reporting, rank, and selection problems.
AB - The suffix tree has proven to be an invaluable indexing data structure, which is widely used as a building block in many applications. We study the problem of making a suffix tree persistent. Specifically, consider a streamed text T where characters are prepended to the beginning of the text. The suffix tree is updated for each character prepended. We wish to allow access to any previous version of the suffix tree. While it is possible to support basic persistence for suffix trees using classical persistence techniques, some applications which can make use of this persistency cannot be solved efficiently using these techniques alone. A collection of such problems is that of queries on string intervals of the text indexed by the suffix tree. In other words, if the text T = t1...tn is indexed, one may want to answer different queries on string intervals, ti...tj , of the text. These types of problems are known as position-restricted and contain querying, reporting, rank, selection etc. Persistency can be utilized to obtain solutions for these problems on prefixes of the text, by solving these problems on previous versions of the suffix tree. However, for substrings it is not sufficient to use the standard persistency. We propose more sophisticated persistent techniques which yield solutions for position-restricted querying, reporting, rank, and selection problems.
UR - http://www.scopus.com/inward/record.url?scp=80053978582&partnerID=8YFLogxK
U2 - 10.1007/978-3-642-24583-1_8
DO - 10.1007/978-3-642-24583-1_8
M3 - ???researchoutput.researchoutputtypes.contributiontobookanthology.conference???
AN - SCOPUS:80053978582
SN - 9783642245824
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 67
EP - 80
BT - String Processing and Information Retrieval - 18th International Symposium, SPIRE 2011, Proceedings
T2 - 18th International Symposium on String Processing and Information Retrieval, SPIRE 2011
Y2 - 17 October 2011 through 21 October 2011
ER -