Encoding Data Structures -- Fast Algorithms for Constrained Graph Density Problems -- The Directed Ring Loading with Penalty Cost -- Edge-Colorings of Weighted Graphs (Extended Abstract) -- Unit Covering in Color-Spanning Set Model -- Compact Encodings and Indexes for the Nearest Larger Neighbor Problem -- A Practical Succinct Data Structure for Tree-Like Graphs -- Forming Plurality at Minimum Cost -- Approximate Distance Oracle in O(n2) Time and O(n) Space for Chordal Graphs -- Straight-Path Queries in Trajectory Data -- Folding a Paper Strip to Minimize Thickness -- An Almost Optimal Algorithm for Voronoi Diagrams of Non-disjoint Line Segments (Extended Abstract) -- PTAS's for Some Metric p-source Communication Spanning Tree Problems -- Fault-Tolerant Gathering of Asynchronous Oblivious Mobile Robots under One-Axis Agreement -- Enumerating Eulerian Trails via Hamiltonian Path Enumeration -- The Impact of Communication Patterns on Distributed Self-Adjusting Binary Search Trees -- An Efficient Silent Self-Stabilizing Algorithm for 1-Maximal Matching in Anonymous Networks -- Dynamic Online Multiselection in Internal and External Memory -- Competitive Analysis for Multi-objective Online Algorithms -- Simultaneous Drawing of Planar Graphs with Right-Angle Crossings and Few Bends -- An Improved Algorithm for Parameterized Edge Dominating Set Problem -- On Bar (1, j)-Visibility Graphs (Extended Abstract) -- Simultaneous Time-Space Upper Bounds for Red-Blue Path Problem in Planar DAGs -- Non-repetitive Strings over Alphabet Lists -- Dichotomy Theorems for Homomorphism Polynomials of Graph Classes -- Common Unfolding of Regular Tetrahedron and Johnson-Zalgaller Solid -- Threshold Circuits for Global Patterns in 2-Dimensional Maps -- Superset Generation on Decision Diagrams -- On Triangle Cover Contact Graphs -- Logspace and FPT Algorithms for Graph Isomorphism for Subclasses of Bounded Tree-Width Graphs.

This book constitutes the thoroughly refereed conference proceedings of the 9th International Workshop on Algorithms and Computation, WALCOM 2015, held in Dhaka, Bangladesh, in February 2015. The 26 revised full papers presented together with 3 invited talks were carefully reviewed and selected from 85 submissions. The papers are organized in topical sections on approximation algorithms, data structures and algorithms, computational geometry, combinatorial algorithms, distributed and online algorithms, graph drawing and algorithms, combinatorial problems and complexity, and graph enumeration and algorithms.