This volume contains the proceedings of the Twelfth Annual International S- posiumonAlgorithmsandComputation(ISAAC2001),heldinChristchurch, NewZealand,19-21December2001. Inthepast,ithasbeenheldinTokyo(1990), Taipei(1991),Nagoya(1992),HongKong(1994),Cairnes(1995),Osaka(1996), Singapore(1997),Taejon,Korea(1998),Madras(1999),andTaipei(2000). Since thethirdinNagoya,theproceedingshavebeenpublishedinSpringer-Verlag's Lecture Notes in Computer Science series. AlthoughthesymposiumrotatesmainlyintheAsia/Paci?cregion,ther- ereeingprocesswasconductedinternationally,andresearchersgatheredfrom allovertheworld. Wereceived124submissionsfrom32countries,ofwhich 62 papers were accepted for presentation at the symposium. The papers of three invited speakers are also included. Submission was conducted electro- cally by CyberChair generously o?ered by the University of Twente. Each paper was reviewed by three or four referees with the assistance of external referees, whose names are listed overleaf. Discussions on how to select papers were also conducted electronically over more than a week. Due to the large number of submittedpapers,thereviewingprocesswasquitechallengingfortheprogram committee. There were many acceptable papers which we could not accom- date into the time frame of the three-day symposium. The best paper award was given to "Computing the Quartet Distance between Evolutionary Trees in Time 2 O(nlog n)"byGerthStoltingBrodal,RolfFagerberg,andChristianNorgaard Storm Pedersen. We hope all accepted papers will eventually appear in scienti?c journals in a more polished form. IntheeraoftheInternet,wetendtothinkwecanexchangeideaswith other researchers instantly without needing to meet. This way we tend to be isolatedunknowingly. BecauseoftheInternet,however,theneedformeeting otherpeoplefacetofaceiseverincreasing. Todoresearch,itisstillbestto seeourpeersdirectly,andgetideasfromtheveryinventers. WehopeISAAC 2001 made a good forum for researchers in algorithms and computation to meet, beingheldinNewZealand,abeautifulsmallnationof3. 8millionpeople. Itis roughlyatthecenterofthewaterhemisphere,meaningthatitisfarthestfrom therestoftheworld. Peoplecanescapefromtheirdailybusinesses,meetpeople, and refresh their thinking. We thank all the authors who submitted papers and contributed to the high quality of the symposium. We thank all the organizing committee members, programcommitteemembers,andexternalrefereeswhosacri?cedtheirtime for the symposium. We thank all the sponsors who made the symposium ?n- ciallyviable.

Table of Contents:
Invited Talk 1.- Chain Reconfiguration The Ins and Outs, Ups and Downs of Moving Polygons and Polygonal Linkages.- Combinatorial Generation and Optimization (I).- Application of M-Convex Submodular Flow Problem to Mathematical Economics.- A Polynomial Time Approximation Scheme for Minimizing Total Completion Time of Unbounded Batch Scheduling.- A Polynomial Time Approximation Scheme for the Multi-vehicle Scheduling Problem on a Path with Release and Handling Times.- Semi-normal Schedulings: Improvement on Goemans’ Algorithm.- Parallel and Distributed Algorithms (I).- Balanced Scheduling toward Loss-Free Packet Queuing and Delay Fairness.- Broadcasting with Universal Lists Revisited: Using Competitive Analysis.- On Adaptive Fault Diagnosis for Multiprocessor Systems.- On-Line Multicasting in All-Optical Networks.- Graph Drawing and Algorithms (I).- Enumerating Floorplans with n Rooms.- On Min-Max Cycle Bases.- On the Minimum Local-Vertex-Connectivity Augmentation in Graphs.- Counting Graph Isomorphisms among Chordal Graphs with Restricted Clique Number.- Computational Geometry (I).- Quantum Algorithms for Intersection and Proximity Problems.- BUSHWHACK: An Approximation Algorithm for Minimal Paths through Pseudo-Euclidean Spaces.- Approximation of Minimum Triangulation for Polyhedron with Bounded Degrees.- Tree-Approximations for the Weighted Cost-Distance Problem.- Computational Complexity and Cryptology.- Necessary and Sufficient Numbers of Cards for Sharing Secret Keys on Hierarchical Groups.- Generic Algorithms and Key Agreement Protocols Based on Group Actions.- Baire Category and Nowhere Differentiability for Feasible Real Functions.- Translation among CNFs, Characteristic Models and Ordered Binary Decision Diagrams.- Automata and Formal Languages.- On Removingthe Pushdown Stack in Reachability Constructions.- A New Recognition Algorithm for Extended Regular Expressions.- Polynomial-Time Algorithms for the Equivalence for One-Way Quantum Finite Automata.- An Index for the Data Size to Extract Decomposable Structures in LAD.- Invited Talk 2.- Parameterized Complexity: The Main Ideas and Some Research Frontiers.- Graph Drawing and Algorithms (II).- Tight Bounds on Maximal and Maximum Matchings.- Recognition and Orientation Algorithms for P4-Comparability Graphs.- Efficient Algorithms for k-Terminal Cuts on Planar Graphs.- Polynomial Time Algorithms for Edge-Connectivity Augmentation of Hamiltonian Paths.- Combinatorial Generation and Optimization (II).- Algorithms for Pattern Involvement in Permutations.- A Fast Algorithm for Enumerating Bipartite Perfect Matchings.- On-Line Scheduling a Batch Processing System to Minimize Total Weighted Job Completion Time.- On the Complexity of Train Assignment Problems.- Computational Biology and String Matching (I).- A Combinatorial Toolbox for Protein Sequence Design and Landscape Analysis in the Grand Canonical Model.- Complexity of Comparing Hidden Markov Models.- DNA Self-Assembly For Constructing 3D Boxes.- Exact Solutions for Closest String and Related Problems.- Computational Geometry (II).- Topological Peeling and Implementation.- Image Segmentation with Monotonicity and Smoothness Constraints.- Optimization Algorithms for Sweeping a Polygonal Region with Mobile Guards.- Approximation of a Geometric Set Covering Problem.- Invited Talk 3.- Shortest Path Algorithms: Engineering Aspects.- Graph Drawing and Algorithms (III).- Efficient Algorithms for Weighted Colorings of Series-Parallel Graphs.- Go with the Winners Algorithms for Cliques in Random Graphs.- Complexity of Partial Coversof Graphs.- On Game-Theoretic Models of Networks.- Parallel and Distributed Algorithms (II).- The Complexity of Some Basic Problems for Dynamic Process Graphs.- Delay Optimizations in Quorum Consensus.- Randomized Shared Queues Applied to Distributed Optimization Algorithms.- Multiprocess Time Queue.- Computational Geometry (III).- Labeling Points with Weights.- Small Convex Quadrangulations of Point Sets.- How to Color a Checkerboard with a Given Distribution — Matrix Rounding Achieving Low 2 × 2-Discrepancy.- Labeling Subway Lines.- Randomized and Approximation Algorithms.- Complexity Study on Two Clustering Problems.- A Modified Greedy Algorithm for the Set Cover Problem with Weights 1 and 2.- A Unified Framework for Approximating Multiway Partition Problems.- On-Line Algorithms for Cardinality Constrained Bin Packing Problems.- Computational Biology and String Matching (II).- Suffix Vector: A Space-Efficient Suffix Tree Representation.- Fragmentary Pattern Matching: Complexity, Algorithms and Applications for Analyzing Classic Literary Works.- Computing the Quartet Distance between Evolutionary Trees in Time O(n log2 n).- Algorithms and Data Structures.- The Cent-dian Path Problem on Tree Networks.- Approximate Hotlink Assignment.- Efficient Algorithms for Two Generalized 2-Median Problems on Trees.