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Illuminating the x-Axis by α-Floodlights

Authors Bengt J. Nilsson , David Orden , Leonidas Palios , Carlos Seara , Paweł Żyliński

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Author Details

Bengt J. Nilsson
  • Department of Computer Science and Media Technology, Malmö University, Sweden
David Orden
  • Physics and Mathematics Department, Universidad de Alcalá, Spain
Leonidas Palios
  • Department of Computer Science and Engineering, University of Ioannina, Greece
Carlos Seara
  • Departament of Mathematics, Universitat Politècnica de Catalunya, Barcelona, Spain
Paweł Żyliński
  • Institute of Informatics, University of Gdańsk, Poland

Cite AsGet BibTex

Bengt J. Nilsson, David Orden, Leonidas Palios, Carlos Seara, and Paweł Żyliński. Illuminating the x-Axis by α-Floodlights. In 32nd International Symposium on Algorithms and Computation (ISAAC 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 212, pp. 11:1-11:12, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)


Given a set S of regions with piece-wise linear boundary and a positive angle α < 90°, we consider the problem of computing the locations and orientations of the minimum number of α-floodlights positioned at points in S which suffice to illuminate the entire x-axis. We show that the problem can be solved in O(n log n) time and O(n) space, where n is the number of vertices of the set S.

Subject Classification

ACM Subject Classification
  • Theory of computation → Computational geometry
  • Computational Geometry
  • Visibility
  • Art Gallery Problems
  • Floodlights


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