Handout 09: Suggested Project Topics
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Compressed Suffix Trees with Full Functionality
Compressed Suffix Trees with Full Functionality Kunihiko Sadakane Department of Computer Science and Communication Engineering, Kyushu University Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581, Japan [email protected] Abstract We introduce new data structures for compressed suffix trees whose size are linear in the text size. The size is measured in bits; thus they occupy only O(n log |A|) bits for a text of length n on an alphabet A. This is a remarkable improvement on current suffix trees which require O(n log n) bits. Though some components of suffix trees have been compressed, there is no linear-size data structure for suffix trees with full functionality such as computing suffix links, string-depths and lowest common ancestors. The data structure proposed in this paper is the first one that has linear size and supports all operations efficiently. Any algorithm running on a suffix tree can also be executed on our compressed suffix trees with a slight slowdown of a factor of polylog(n). 1 Introduction Suffix trees are basic data structures for string algorithms [13]. A pattern can be found in time proportional to the pattern length from a text by constructing the suffix tree of the text in advance. The suffix tree can also be used for more complicated problems, for example finding the longest repeated substring in linear time. Many efficient string algorithms are based on the use of suffix trees because this does not increase the asymptotic time complexity. A suffix tree of a string can be constructed in linear time in the string length [28, 21, 27, 5]. -
C Programming: Data Structures and Algorithms
C Programming: Data Structures and Algorithms An introduction to elementary programming concepts in C Jack Straub, Instructor Version 2.07 DRAFT C Programming: Data Structures and Algorithms, Version 2.07 DRAFT C Programming: Data Structures and Algorithms Version 2.07 DRAFT Copyright © 1996 through 2006 by Jack Straub ii 08/12/08 C Programming: Data Structures and Algorithms, Version 2.07 DRAFT Table of Contents COURSE OVERVIEW ........................................................................................ IX 1. BASICS.................................................................................................... 13 1.1 Objectives ...................................................................................................................................... 13 1.2 Typedef .......................................................................................................................................... 13 1.2.1 Typedef and Portability ............................................................................................................. 13 1.2.2 Typedef and Structures .............................................................................................................. 14 1.2.3 Typedef and Functions .............................................................................................................. 14 1.3 Pointers and Arrays ..................................................................................................................... 16 1.4 Dynamic Memory Allocation ..................................................................................................... -
Suffix Trees
JASS 2008 Trees - the ubiquitous structure in computer science and mathematics Suffix Trees Caroline L¨obhard St. Petersburg, 9.3. - 19.3. 2008 1 Contents 1 Introduction to Suffix Trees 3 1.1 Basics . 3 1.2 Getting a first feeling for the nice structure of suffix trees . 4 1.3 A historical overview of algorithms . 5 2 Ukkonen’s on-line space-economic linear-time algorithm 6 2.1 High-level description . 6 2.2 Using suffix links . 7 2.3 Edge-label compression and the skip/count trick . 8 2.4 Two more observations . 9 3 Generalised Suffix Trees 9 4 Applications of Suffix Trees 10 References 12 2 1 Introduction to Suffix Trees A suffix tree is a tree-like data-structure for strings, which affords fast algorithms to find all occurrences of substrings. A given String S is preprocessed in O(|S|) time. Afterwards, for any other string P , one can decide in O(|P |) time, whether P can be found in S and denounce all its exact positions in S. This linear worst case time bound depending only on the length of the (shorter) string |P | is special and important for suffix trees since an amount of applications of string processing has to deal with large strings S. 1.1 Basics In this paper, we will denote the fixed alphabet with Σ, single characters with lower-case letters x, y, ..., strings over Σ with upper-case or Greek letters P, S, ..., α, σ, τ, ..., Trees with script letters T , ... and inner nodes of trees (that is, all nodes despite of root and leaves) with lower-case letters u, v, ... -
Advanced Data Structures
Advanced Data Structures PETER BRASS City College of New York CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521880374 © Peter Brass 2008 This publication is in copyright. Subject to statutory exception and to the provision of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published in print format 2008 ISBN-13 978-0-511-43685-7 eBook (EBL) ISBN-13 978-0-521-88037-4 hardback Cambridge University Press has no responsibility for the persistence or accuracy of urls for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. Contents Preface page xi 1 Elementary Structures 1 1.1 Stack 1 1.2 Queue 8 1.3 Double-Ended Queue 16 1.4 Dynamical Allocation of Nodes 16 1.5 Shadow Copies of Array-Based Structures 18 2 Search Trees 23 2.1 Two Models of Search Trees 23 2.2 General Properties and Transformations 26 2.3 Height of a Search Tree 29 2.4 Basic Find, Insert, and Delete 31 2.5ReturningfromLeaftoRoot35 2.6 Dealing with Nonunique Keys 37 2.7 Queries for the Keys in an Interval 38 2.8 Building Optimal Search Trees 40 2.9 Converting Trees into Lists 47 2.10 -
Search Trees
Lecture III Page 1 “Trees are the earth’s endless effort to speak to the listening heaven.” – Rabindranath Tagore, Fireflies, 1928 Alice was walking beside the White Knight in Looking Glass Land. ”You are sad.” the Knight said in an anxious tone: ”let me sing you a song to comfort you.” ”Is it very long?” Alice asked, for she had heard a good deal of poetry that day. ”It’s long.” said the Knight, ”but it’s very, very beautiful. Everybody that hears me sing it - either it brings tears to their eyes, or else -” ”Or else what?” said Alice, for the Knight had made a sudden pause. ”Or else it doesn’t, you know. The name of the song is called ’Haddocks’ Eyes.’” ”Oh, that’s the name of the song, is it?” Alice said, trying to feel interested. ”No, you don’t understand,” the Knight said, looking a little vexed. ”That’s what the name is called. The name really is ’The Aged, Aged Man.’” ”Then I ought to have said ’That’s what the song is called’?” Alice corrected herself. ”No you oughtn’t: that’s another thing. The song is called ’Ways and Means’ but that’s only what it’s called, you know!” ”Well, what is the song then?” said Alice, who was by this time completely bewildered. ”I was coming to that,” the Knight said. ”The song really is ’A-sitting On a Gate’: and the tune’s my own invention.” So saying, he stopped his horse and let the reins fall on its neck: then slowly beating time with one hand, and with a faint smile lighting up his gentle, foolish face, he began.. -
The Random Access Zipper: Simple, Purely-Functional Sequences
The Random Access Zipper: Simple, Purely-Functional Sequences Kyle Headley and Matthew A. Hammer University of Colorado Boulder [email protected], [email protected] Abstract. We introduce the Random Access Zipper (RAZ), a simple, purely-functional data structure for editable sequences. The RAZ com- bines the structure of a zipper with that of a tree: like a zipper, edits at the cursor require constant time; by leveraging tree structure, relocating the edit cursor in the sequence requires log time. While existing data structures provide these time bounds, none do so with the same simplic- ity and brevity of code as the RAZ. The simplicity of the RAZ provides the opportunity for more programmers to extend the structure to their own needs, and we provide some suggestions for how to do so. 1 Introduction The singly-linked list is the most common representation of sequences for func- tional programmers. This structure is considered a core primitive in every func- tional language, and morever, the principles of its simple design recur througout user-defined structures that are \sequence-like". Though simple and ubiquitous, the functional list has a serious shortcoming: users may only efficiently access and edit the head of the list. In particular, random accesses (or edits) generally require linear time. To overcome this problem, researchers have developed other data structures representing (functional) sequences, most notably, finger trees [8]. These struc- tures perform well, allowing edits in (amortized) constant time and moving the edit location in logarithmic time. More recently, researchers have proposed the RRB-Vector [14], offering a balanced tree representation for immutable vec- tors. -
Design of Data Structures for Mergeable Trees∗
Design of Data Structures for Mergeable Trees∗ Loukas Georgiadis1; 2 Robert E. Tarjan1; 3 Renato F. Werneck1 Abstract delete(v): Delete leaf v from the forest. • Motivated by an application in computational topology, merge(v; w): Given nodes v and w, let P be the path we consider a novel variant of the problem of efficiently • from v to the root of its tree, and let Q be the path maintaining dynamic rooted trees. This variant allows an from w to the root of its tree. Restructure the tree operation that merges two tree paths. In contrast to the or trees containing v and w by merging the paths P standard problem, in which only one tree arc at a time and Q in a way that preserves the heap order. The changes, a single merge operation can change many arcs. merge order is unique if all node labels are distinct, In spite of this, we develop a data structure that supports which we can assume without loss of generality: if 2 merges and all other standard tree operations in O(log n) necessary, we can break ties by node identifier. See amortized time on an n-node forest. For the special case Figure 1. that occurs in the motivating application, in which arbitrary arc deletions are not allowed, we give a data structure with 1 an O(log n) amortized time bound per operation, which is merge(6,11) asymptotically optimal. The analysis of both algorithms is 3 2 not straightforward and requires ideas not previously used in 6 7 4 5 the study of dynamic trees. -
Lecture 1: Introduction
Lecture 1: Introduction Agenda: • Welcome to CS 238 — Algorithmic Techniques in Computational Biology • Official course information • Course description • Announcements • Basic concepts in molecular biology 1 Lecture 1: Introduction Official course information • Grading weights: – 50% assignments (3-4) – 50% participation, presentation, and course report. • Text and reference books: – T. Jiang, Y. Xu and M. Zhang (co-eds), Current Topics in Computational Biology, MIT Press, 2002. (co-published by Tsinghua University Press in China) – D. Gusfield, Algorithms for Strings, Trees, and Sequences: Computer Science and Computational Biology, Cambridge Press, 1997. – D. Krane and M. Raymer, Fundamental Concepts of Bioin- formatics, Benjamin Cummings, 2003. – P. Pevzner, Computational Molecular Biology: An Algo- rithmic Approach, 2000, the MIT Press. – M. Waterman, Introduction to Computational Biology: Maps, Sequences and Genomes, Chapman and Hall, 1995. – These notes (typeset by Guohui Lin and Tao Jiang). • Instructor: Tao Jiang – Surge Building 330, x82991, [email protected] – Office hours: Tuesday & Thursday 3-4pm 2 Lecture 1: Introduction Course overview • Topics covered: – Biological background introduction – My research topics – Sequence homology search and comparison – Sequence structural comparison – string matching algorithms and suffix tree – Genome rearrangement – Protein structure and function prediction – Phylogenetic reconstruction * DNA sequencing, sequence assembly * Physical/restriction mapping * Prediction of regulatiory elements • Announcements: -
Open Data Structures (In Java)
Open Data Structures (in Java) Edition 0.1G Pat Morin Contents Acknowledgments ix Why This Book? xi 1 Introduction 1 1.1 The Need for Efficiency ..................... 2 1.2 Interfaces ............................. 4 1.2.1 The Queue, Stack, and Deque Interfaces . 5 1.2.2 The List Interface: Linear Sequences . 6 1.2.3 The USet Interface: Unordered Sets .......... 8 1.2.4 The SSet Interface: Sorted Sets ............ 9 1.3 Mathematical Background ................... 9 1.3.1 Exponentials and Logarithms . 10 1.3.2 Factorials ......................... 11 1.3.3 Asymptotic Notation . 12 1.3.4 Randomization and Probability . 15 1.4 The Model of Computation ................... 18 1.5 Correctness, Time Complexity, and Space Complexity . 19 1.6 Code Samples .......................... 22 1.7 List of Data Structures ..................... 22 1.8 Discussion and Exercises .................... 26 2 Array-Based Lists 29 2.1 ArrayStack: Fast Stack Operations Using an Array . 30 2.1.1 The Basics ........................ 30 2.1.2 Growing and Shrinking . 33 2.1.3 Summary ......................... 35 Contents 2.2 FastArrayStack: An Optimized ArrayStack . 35 2.3 ArrayQueue: An Array-Based Queue . 36 2.3.1 Summary ......................... 40 2.4 ArrayDeque: Fast Deque Operations Using an Array . 40 2.4.1 Summary ......................... 43 2.5 DualArrayDeque: Building a Deque from Two Stacks . 43 2.5.1 Balancing ......................... 47 2.5.2 Summary ......................... 49 2.6 RootishArrayStack: A Space-Efficient Array Stack . 49 2.6.1 Analysis of Growing and Shrinking . 54 2.6.2 Space Usage ....................... 54 2.6.3 Summary ......................... 55 2.6.4 Computing Square Roots . 56 2.7 Discussion and Exercises ................... -
Suffix Trees for Fast Sensor Data Forwarding
Suffix Trees for Fast Sensor Data Forwarding Jui-Chieh Wub Hsueh-I Lubc Polly Huangac Department of Electrical Engineeringa Department of Computer Science and Information Engineeringb Graduate Institute of Networking and Multimediac National Taiwan University [email protected], [email protected], [email protected] Abstract— In data-centric wireless sensor networks, data are alleviates the effort of node addressing and address reconfig- no longer sent by the sink node’s address. Instead, the sink uration in large-scale mobile sensor networks. node sends an explicit interest for a particular type of data. The source and the intermediate nodes then forward the data Forwarding in data-centric sensor networks is particularly according to the routing states set by the corresponding interest. challenging. It involves matching of the data content, i.e., This data-centric style of communication is promising in that it string-based attributes and values, instead of numeric ad- alleviates the effort of node addressing and address reconfigura- dresses. This content-based forwarding problem is well studied tion. However, when the number of interests from different sinks in the domain of publish-subscribe systems. It is estimated increases, the size of the interest table grows. It could take 10s to 100s milliseconds to match an incoming data to a particular in [3] that the time it takes to match an incoming data to a interest, which is orders of mangnitude higher than the typical particular interest ranges from 10s to 100s milliseconds. This transmission and propagation delay in a wireless sensor network. processing delay is several orders of magnitudes higher than The interest table lookup process is the bottleneck of packet the propagation and transmission delay. -
Bulk Updates and Cache Sensitivity in Search Trees
BULK UPDATES AND CACHE SENSITIVITY INSEARCHTREES TKK Research Reports in Computer Science and Engineering A Espoo 2009 TKK-CSE-A2/09 BULK UPDATES AND CACHE SENSITIVITY INSEARCHTREES Doctoral Dissertation Riku Saikkonen Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Faculty of Information and Natural Sciences, Helsinki University of Technology for public examination and debate in Auditorium T2 at Helsinki University of Technology (Espoo, Finland) on the 4th of September, 2009, at 12 noon. Helsinki University of Technology Faculty of Information and Natural Sciences Department of Computer Science and Engineering Teknillinen korkeakoulu Informaatio- ja luonnontieteiden tiedekunta Tietotekniikan laitos Distribution: Helsinki University of Technology Faculty of Information and Natural Sciences Department of Computer Science and Engineering P.O. Box 5400 FI-02015 TKK FINLAND URL: http://www.cse.tkk.fi/ Tel. +358 9 451 3228 Fax. +358 9 451 3293 E-mail: [email protected].fi °c 2009 Riku Saikkonen Layout: Riku Saikkonen (except cover) Cover image: Riku Saikkonen Set in the Computer Modern typeface family designed by Donald E. Knuth. ISBN 978-952-248-037-8 ISBN 978-952-248-038-5 (PDF) ISSN 1797-6928 ISSN 1797-6936 (PDF) URL: http://lib.tkk.fi/Diss/2009/isbn9789522480385/ Multiprint Oy Espoo 2009 AB ABSTRACT OF DOCTORAL DISSERTATION HELSINKI UNIVERSITY OF TECHNOLOGY P.O. Box 1000, FI-02015 TKK http://www.tkk.fi/ Author Riku Saikkonen Name of the dissertation Bulk Updates and Cache Sensitivity in Search Trees Manuscript submitted 09.04.2009 Manuscript revised 15.08.2009 Date of the defence 04.09.2009 £ Monograph ¤ Article dissertation (summary + original articles) Faculty Faculty of Information and Natural Sciences Department Department of Computer Science and Engineering Field of research Software Systems Opponent(s) Prof. -
Suffix Trees and Suffix Arrays in Primary and Secondary Storage Pang Ko Iowa State University
Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2007 Suffix trees and suffix arrays in primary and secondary storage Pang Ko Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Bioinformatics Commons, and the Computer Sciences Commons Recommended Citation Ko, Pang, "Suffix trees and suffix arrays in primary and secondary storage" (2007). Retrospective Theses and Dissertations. 15942. https://lib.dr.iastate.edu/rtd/15942 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Suffix trees and suffix arrays in primary and secondary storage by Pang Ko A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Computer Engineering Program of Study Committee: Srinivas Aluru, Major Professor David Fern´andez-Baca Suraj Kothari Patrick Schnable Srikanta Tirthapura Iowa State University Ames, Iowa 2007 UMI Number: 3274885 UMI Microform 3274885 Copyright 2007 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, MI 48106-1346 ii DEDICATION To my parents iii TABLE OF CONTENTS LISTOFTABLES ................................... v LISTOFFIGURES .................................. vi ACKNOWLEDGEMENTS. .. .. .. .. .. .. .. .. .. ... .. .. .. .. vii ABSTRACT....................................... viii CHAPTER1. INTRODUCTION . 1 1.1 SuffixArrayinMainMemory .