Searching a Circular Corridor with Two Flashlights

  • Bo Jiang
  • Xuehou Tan
Part of the Lecture Notes in Computer Science book series (LNCS, volume 5532)


We consider the problem of searching for a mobile intruder in a circular corridor (a polygon with one polygonal hole) by two searchers, who hold a flashlight. Both searchers move on the outer boundary, directing their flashlights at the inner boundary. The objective is to decide whether there exists a search schedule for the searchers to detect the intruder, no matter how fast he moves. We give a characterization of the class of circular corridors, which are searchable with two flashlights. Based on our characterization, an O(n logn) time algorithm is then presented to determine the searchability of a circular corridor with two flashlights, where n denotes the total number of vertices of the outer and inner boundaries. Moreover, a search schedule can be output in time linear in its size, if it exists. Our result gives the first efficient solution to the polygon search problem for two searchers.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Bo Jiang
    • 1
  • Xuehou Tan
    • 1
    • 2
  1. 1.School of Inform. Sci. and Tech.Dalian Martime UniversityChina
  2. 2.Tokai UniversityNumazuJapan

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