Invited Talks -- A Separator Theorem for String Graphs and Its Applications -- Foundations of Exact Rounding -- Approximating Shortest Paths in Graphs -- Line Transversals and Pinning Numbers -- Computational Geometry -- Algorithms for Computing Diffuse Reflection Paths in Polygons -- Shortest Gently Descending Paths -- All Farthest Neighbors in the Presence of Highways and Obstacles -- Improved Algorithm for a Widest 1-Corner Corridor -- Maximum Neighbour Voronoi Games -- On Exact Solutions to the Euclidean Bottleneck Steiner Tree Problem -- Graph Algorithms -- Colinear Coloring on Graphs -- Recursive Generation of 5-Regular Planar Graphs -- Efficient Enumeration of Ordered Trees with k Leaves (Extended Abstract) -- Generating All Triangulations of Plane Graphs (Extended Abstract) -- Recognition of Unigraphs through Superposition of Graphs (Extended Abstract) -- Random Generation and Enumeration of Proper Interval Graphs -- A Fully Dynamic Graph Algorithm for Recognizing Proper Interval Graphs -- Minmax Tree Cover in the Euclidean Space -- Network Design with Weighted Degree Constraints -- Minimum Cuts of Simple Graphs in Almost Always Linear Time -- The Generalized Stable Allocation Problem -- Crossing-Optimal Acyclic Hamiltonian Path Completion and Its Application to Upward Topological Book Embeddings -- Core and Conditional Core Path of Specified Length in Special Classes of Graphs -- Complexity -- The Planar k-Means Problem is NP-Hard -- On the Computational Complexity of Monotone Constraint Satisfaction Problems -- Parameterized Complexity of Stabbing Rectangles and Squares in the Plane -- Graph Drawing -- Straight-Line Grid Drawings of Label-Constrained Outerplanar Graphs with O(n logn) Area (Extended Abstract) -- Matched Drawability of Graph Pairs and of Graph Triples -- An Improved Upward Planarity Testing Algorithm and Related Applications -- Spherical-Rectangular Drawings -- Approximation Algorithms -- The Exemplar Breakpoint Distance for Non-trivial Genomes Cannot Be Approximated -- The Minimal Manhattan Network Problem in Three Dimensions -- Randomized Algorithms -- Shape Matching by Random Sampling -- Object Caching for Queries and Updates.

This book constitutes the refereed proceedings of the Third International Workshop on Algorithms and Computation, WALCOM 2009, held in Kolkata, India, in February 2009. The 30 revised full papers presented together with 4 invited papers were carefully reviewed and selected from 102 submissions. The papers feature original research in the areas of design and analysis of algorithms, computational geometry, graph drawing and graph algorithms. The papers are organized in topical sections on computational geometry, graph algorithms, complexity, graph drawing, approximation algorithms, and randomized algorithms.