Lecture Notes in 1272 Edited by G. Goos, J. Hartmanis and J. van Leeuwen

Advisory Board: W. Brauer D. Gries J. Stoer Frank Dehne Andrew Rau-Chaplin J6rg-Riidiger Sack Roberto Tamassia (Eds.) and Data Structures

5th International Workshop, WADS'97 Halifax, Nova Scotia, Canada August 6-8, 1997 Proceedings

~ Springer Series Editors Gerhard Goos, Karlsruhe University, Germany Juris Hartmanis, Cornell University, NY, USA Jan van Leeuwen, Utrecht University, The

Volume Editors Frank Dehne J/Srg-Rtidiger Sack Carleton University, School of Computer Science 1125 Colonel By Drive, Ottawa, Canada K1S 5B6 E-mail: (dehne/sack) @scs.carleton.ca

Andrew Rau-Chaplin Technical University of Nova Scotia, Department of Computer Science RO. Box 1000, Halifax, Nova Scotia, Canada B3J 2X4 E-mail: [email protected]

Roberto Tamassia Brown University, Center for Geometric Computing Providence, RI 02912-1910, USA E-mail: [email protected]

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Algorithms and data structures : 5th international workshop ; proceedings / WADS '97, Halifax, Nova Scotia, Canada, August 6 - 8, 1997. Frank Dehne ... (ed.). - Berlin ; Heidelberg ; New York ; Barcelona ; Budapest ; Hong Kong ; London ; Milan ; Paris ; Santa Clara ; Singapore ; Tokyo : Springer, 1997 (Lecture notes in computer science ; Vol. 1272) ISBN 3-540-63307-3 CR Subject Classification (1991): Et-2, E.I, G.2, 1.3.5, H.3.3 ISSN 0302-9743 ISBN 3-540-63307-3 Springer-Verlag Berlin Heidelberg New York

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The papers in this volume were presented at the 1997 Workshop on Algorithms and Data Structures (WADS '97). The workshop took place from August 6 to 8, 1997, at TUNS/Dalhousie University in Halifax, Nova Scotia and was sponsored Carleton University and TUNS/Dalhousie University. In response to the program committee's call for papers, 8 1 papers where submitted. From these submissions, the program committee selected 37 papers for presentation at the workshop. In addition to these papers, the workshop included invited presentations Bernard Chazelle, David Dobkin, S. Rao Kosaraju, Ketan Mulmuley, and .

F. Dehne, A. Rau-Chaplin, J.-R. Sack and R. Tamassia August, 1997

WADS Steering Committee F. Dehne (Carleton), I. Munro (Waterloo), J.-R. Sack (Carleton), N. Santoro (Carleton), R. Tamassia (Brown)

WADS'97 Program Committee Co-chairs: F. Dehne (Carleton), A. Rau-Chaplin (TUNS/DaI.), J.-R. Sack (Carleton), R. Tamassia (Brown). A. Anderson (Lund), A. Apostolico (Purdue and Padova), G. Ausiello (Rome), C. Bajaj (Purdue), R. Cypher (Johns Hopkins), L. De Floriani (Genova), L. Devroye (McGill), D. Eppstein (Univ. of Calif. at Irvine), M. Farach (Rutgers), A. Ferreira (Ecole Norm. Sup. de Lyon), P. Fraignaud (Ecole Norm. Sup. de Lyon), G. Frederickson (Purdue), M. Goodrich (Johns Hopkins), H. Juergensen (Univ. of Western Ontario), E. Kranakis (Carleton), H.P. Kriegel (Muenchen), D.T. Lee (Northwestern), T. Lengauer (GMD), L. Pagli (Pisa), G. Plaxton (Univ. of Texas at Austin), J. Reif (Duke), N. Santoro (Carleton), P.G. Spirakis (Patras), H. Sudborough (Univ. of Texas at Dallas), P. Vitanyi (CWI), P. Widmayer (ETH), C.K. Wong (Chinese Univ. of Hong Kong).

WADS'97 Conference Chair A. Rau-Chaplin (TUNS/Dal.) TABLE OF CONTENTS Session 1: INVITED LECTURE Discrepancy Theory and Computational Geometry Bernard Chazelle Session 2A Dynamic in Low Obstacle Density Environments Robert-Paul Berretty, Mark Overmars and A. Frank van der Stappen 3 Visibility-Based Pursuit-Evasion in a Polygonal Environment Leonidas J. Guibas, Jean-Claude Latombe, Steven M. LaValle, David Lin and Rajeev Motwani 17 Maintaining the Extent of a Moving Point Set Pankaj K. Agarwal, Leonidas J. Guibas, John Hershberger and Eric Veach 31 Session 2B Finding Cores of Limited Length Stephen Alstrup, Peter W. Lauridsen, Peer Sommerlund and Mikkel Thorup 45 On Bipartite Crossings, Largest Biptanar Subgraphs, and the Linear Arrangement Problem Farhad Shahrokhi, Ondrej S~kora, L~.szl6 Sz6kely and Imrich Vrt6 55 Session 3: INVITED LECTURE Approximation Algorithms for a Genetic Diagnostics Problem S. Rao Kosaraju, Alejandro A. Schaeffer and Leslie G. Biesecker 69 Session 4A Cartographic Line Simplification and Polygon CSG Formulae in O(n Log'n) Time John Hershberger and Jack Snoeyink 93 Constrained TSP and Low-Power Computing , Rajeev Motwani, Prabhakar Raghavan and Craig Silverstein 104 VIII

Session 4B On-Line Load Balancing for Related Machines Piotr Berman, Moses Charikar and Marek Karpinski 116 A Linear-Time for the 1-Mismatch Problem Nikola Stojanovic, Piotr Berman, Deborah Gumucio, Ross Hardison and Webb Miller 126 Session 5A On Some Geometric Optimization Problems in Layered Manufacturing Jayanth Majhi, Ravi Janardan, Michiel Smid and Prosenjit Gupta 136 New TSP Construction Heuristics and Their Relationships To The 2-Opt Hiroyuki Okano, Shinji Misono and Kazuo Iwano 150 Session 5B Pattern Matching in Hypertext Amihood Amir, Moshe Lewenstein and Noa Lewenstein 160 Multiple Approximate String Matching Ricardo Baeza-Yates and Gonzalo Navarro 174 Session 6: INVITED LECTURE Applied Computational Geometry David P. Dobkin 185 Session 7A Checking the Convexity of Polytopes and the Planarity of Subdivisions O. Devillers, G. Liotta, F. P. Preparata and R. Tamassia 186 Voronoi Diagrams for Polygon-Offset Distance Functions Gill Barequet, Matthew T. Dickerson and Michael T. Goodrich 200 Session 7B Randomized Algorithms for that Ancient Scheduling Problem Steve Selden 210 Optimal Parallel Algorithms for Proximate Points, with Appfications Tatsuya Hayashi, Koji Nakano and Stephan Olariu 224 IX

Session 8A An Efficient A/gorithm for Shortest Paths in Vertica/ and Horizonta/ Segments David Eppstein and David W. Hart 234 On Geometric Path Query Problems Danny Z. Chen, Ovidiu Daescu and Kevin S. Klenk 248 Session 8B On-Line Scheduling with Hard Deadlines Sally A. Goldman, Jyoti Parwatikar and Subhash Suri 258 Load Balanced Mapping of Data Structures in Parallel Memory Modules for Fast and Conflict-Free Templates Access Sajal K. Das and M. Cristina Pinotti 272 Session 9: INVITED LECTURE Para//e/ vs. Parametric Comp/exity Ketan Mulmuley 282 Session 10A Position-/ndependent Near Optima/Searching and On- Line Recognition in Star Po/ygons Alejandro Lopez-Ortiz and Sven Schuierer 284 Dynamic Data Structures for Fat Objects and Their App/ications Alon Efrat, Matthew J. Katz, Franck Nielsen and Micha Sharir 297 /ntractabi/ity of Assemb/y Sequencing: Unit Disks in the P/ane Michael Goldwasser and Rajeev Motwani 307 On Hami/tonian Triangu/ations in Simp/e Po/ygons Giri Narasimhan 321 Session 10B Computing Orthogona/ Drawings with the Minimum Number of Bends Paola Bertolazzi, Giuseppe Di Battista and Walter Didimo 331 On a simp/e Depth-First Search Strategy for Exp/oring Unknown Graphs Stephen Kwek 345 Orthogonal Drawing of High Degree Graphs with Small Area and Few Bends Achilleas Papakostas and Ioannis G. Tollis 354 A Centroid Labeling Technique and Its Application to Path Selection in Trees Sarnath Ramnath and Hong Shen 368 Session 11A Offset-Polygon Annulus Placement Problems Gill Barequet, Amy J. Briggs, Matthew T. Dickerson and Michael T. Goodrich 378 Computing Constrained Minimum-Width Annull of Point Sets , Prosenjit Bose, David Bremner, Suneeta Ramaswami and Gordon Wilfong 392 Geometric Applications of Posets Michael Segal and Klara Kedem 402 Constructing Pairwise Disjoint Paths with Few Links Himanshu Gupta and Rephael Wenger 416 Session 11B Trans-dichotomous Algorithms without Multiplication - Some Upper and Lower Bounds Andrej Brodnik, Peter Bro Miltersen and J. lan Munro 426 An Approximation Algorithm for Stacking up Bins from a Conveyer onto Pallets Jochen Rethman and Egon Wanke 440 Relaxed Balance through Standard Rotations Kim S. Larsen, Eljas Soisalon-Soininen and Peter Widmayer 450 Efficient Breakout Routing in Printed Circuit Boards John Hershberger and Subhash Suri 462 Session 12: INVITED LECTURE Planarity Revisited Zhi-Zhong Chen, Michelangelo Grigni and Christos Papadimitriou 472 Author Index 475