This volume contains the papers presented at the 11th Algorithms and Data Structures Symposium, WADS 2009 (formerly Workshop on Algorithms and Data Structures), held during August 21–23, 2009 in Ban?, Alberta, Canada. WADS alternates with the Scandinavian Workshop on Algorithms Theory (SWAT), continuing the tradition of SWAT and WADS starting with SWAT 1988 and WADS 1989. Inresponsetothecallforpapers,126papersweresubmitted. Fromtheses- missions, the ProgramCommittee selected 49 papers for presentation at WADS 2009. In addition, invited lectures were given by the following distinguished researchers: Erik Demaine, Richard Karp, and Christos Papadimitriou. On behalf of the Program Committee, we would like to express our appre- ation to the invited speakers, reviewers and all authors who submitted papers. May 2009 Frank Dehne Marina Gavrilova J¨ org-Ru ¨diger Sack Csaba D. T´ oth Conference Organization Program Chairs Frank Dehne Marina Gavrilova Joerg-Ruediger Sack Csaba D. Toth Program Committee Sergei Bereg Allan Borodin Gerth Stolting Brodal Timothy Chan Mark de Berg Frank Devai Matt Duckham Rolf Fagerberg Randolph Franklin Joachim Gudmundsson Susanne Hambrusch Rolf Klein Mike Langston Ming Li Friedhelm Meyer auf der Heide Ian Munro Jon Rokne Shashi Shekhar Bettina Speckmann Paul Spirakis Gabor Tardos Je? Vitter Frances F. Yao Local Organization Marina Gavrilova Csaba D. Toth Jon Rokne Maruf Monwar Kushan Ahmadian Table of Contents On the Power of the Semi-Separated Pair Decomposition. . . . . . . . . . . . . . 1 Mohammad Ali Abam, Paz Carmi, Mohammad Farshi, and Michiel Smid Plane Graphs with Parity Constraints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

On the Power of the Semi-Separated Pair Decomposition.- Plane Graphs with Parity Constraints.- Straight-Line Rectangular Drawings of Clustered Graphs.- Online Priority Steiner Tree Problems.- Connect the Dot: Computing Feed-Links with Minimum Dilation.- Minimal Locked Trees.- Approximating Transitive Reductions for Directed Networks.- 1.25-Approximation Algorithm for Steiner Tree Problem with Distances 1 and 2.- Succinct Orthogonal Range Search Structures on a Grid with Applications to Text Indexing.- A Distribution-Sensitive Dictionary with Low Space Overhead.- A Comparison of Performance Measures for Online Algorithms.- Delaunay Triangulation of Imprecise Points Simplified and Extended.- An Improved SAT Algorithm in Terms of Formula Length.- Shortest Path Problems on a Polyhedral Surface.- Approximation Algorithms for Buy-at-Bulk Geometric Network Design.- Rank-Sensitive Priority Queues.- Algorithms Meet Art, Puzzles, and Magic.- Skip-Splay: Toward Achieving the Unified Bound in the BST Model.- Drawing Graphs with Right Angle Crossings.- Finding a Hausdorff Core of a Polygon: On Convex Polygon Containment with Bounded Hausdorff Distance.- Efficient Construction of Near-Optimal Binary and Multiway Search Trees.- On the Approximability of Geometric and Geographic Generalization and the Min-Max Bin Covering Problem.- On Reconfiguration of Disks in the Plane and Related Problems.- Orientation-Constrained Rectangular Layouts.- The h-Index of a Graph and Its Application to Dynamic Subgraph Statistics.- Optimal Embedding into Star Metrics.- Online Square Packing.- Worst-Case Optimal Adaptive Prefix Coding.- New Results on Visibility in Simple Polygons.- Dynamic Graph Clustering Using Minimum-Cut Trees.- Rank-Balanced Trees.- Approximation Algorithms for Finding a Minimum Perimeter Polygon Intersecting a Set of Line Segments.- Reconfiguration of List Edge-Colorings in a Graph.- The Simultaneous Representation Problem for Chordal, Comparability and Permutation Graphs.- Two for One: Tight Approximation of 2D Bin Packing.- Fault Tolerant External Memory Algorithms.- Inspecting a Set of Strips Optimally.- A Pseudopolynomial Algorithm for Alexandrov’s Theorem.- A Scheme for Computing Minimum Covers within Simple Regions.- Better Approximation Algorithms for the Maximum Internal Spanning Tree Problem.- Two Approximation Algorithms for ATSP with Strengthened Triangle Inequality.- Streaming Embeddings with Slack.- Computing the Implicit Voronoi Diagram in Triple Precision.- Efficient Approximation of Combinatorial Problems by Moderately Exponential Algorithms.- Integer Programming: Optimization and Evaluation Are Equivalent.- Resolving Loads with Positive Interior Stresses.- On Making Directed Graphs Transitive.- Bit-Parallel Tree Pattern Matching Algorithms for Unordered Labeled Trees.- Compact and Low Delay Routing Labeling Scheme for Unit Disk Graphs.

This volume contains the papers presented at the 11th Algorithms and Data Structures Symposium, WADS 2009 (formerly Workshop on Algorithms and Data Structures), held during August 21–23, 2009 in Ban?, Alberta, Canada. WADS alternates with the Scandinavian Workshop on Algorithms Theory (SWAT), continuing the tradition of SWAT and WADS starting with SWAT 1988 and WADS 1989. Inresponsetothecallforpapers,126papersweresubmitted. Fromtheses- missions, the ProgramCommittee selected 49 papers for presentation at WADS 2009. In addition, invited lectures were given by the following distinguished researchers: Erik Demaine, Richard Karp, and Christos Papadimitriou. On behalf of the Program Committee, we would like to express our appre- ation to the invited speakers, reviewers and all authors who submitted papers. May 2009 Frank Dehne Marina Gavrilova J¨ org-Ru ¨diger Sack Csaba D. T´ oth Conference Organization Program Chairs Frank Dehne Marina Gavrilova Joerg-Ruediger Sack Csaba D. Toth Program Committee Sergei Bereg Allan Borodin Gerth Stolting Brodal Timothy Chan Mark de Berg Frank Devai Matt Duckham Rolf Fagerberg Randolph Franklin Joachim Gudmundsson Susanne Hambrusch Rolf Klein Mike Langston Ming Li Friedhelm Meyer auf der Heide Ian Munro Jon Rokne Shashi Shekhar Bettina Speckmann Paul Spirakis Gabor Tardos Je? Vitter Frances F. Yao Local Organization Marina Gavrilova Csaba D. Toth Jon Rokne Maruf Monwar Kushan Ahmadian Table of Contents On the Power of the Semi-Separated Pair Decomposition. . . . . . . . . . . . . . 1 Mohammad Ali Abam, Paz Carmi, Mohammad Farshi, and Michiel Smid Plane Graphs with Parity Constraints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .