Improved algorithms for farthest colored voronoi diagram of segments

  • Authors:
  • Yongding Zhu;Jinhui Xu

  • Affiliations:
  • Department of Computer Science and Engineering, State University of New York at Buffalo, Buffalo, NY;Department of Computer Science and Engineering, State University of New York at Buffalo, Buffalo, NY

  • Venue:
  • COCOA'11 Proceedings of the 5th international conference on Combinatorial optimization and applications
  • Year:
  • 2011

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Abstract

Given n line segments in the plane with each colored by one of k colors, the Farthest Colored Voronoi Diagram (FCVD) is a subdivision of the plane such that the region of a c-colored site (segment or subsegment) s contains all points of the plane for which c is the farthest color and s is the nearest c-colored site. FCVD is a generalization of the Farthest Voronoi Diagram (i.e., k = n) and the regular Voronoi Diagram (i.e., k = 1). In this paper, we first present a simple algorithm to solve the general FCVD problem in an output-sensitive fashion in O((kn + I)α(H) log n) time, where I is the number of intersections of the input and H is the complexity of the FCVD. We then focus on a special case, called Farthest-polygon Voronoi Diagram (FPVD), in which all colored segments form k disjoint polygonal structures (i.e., simple polygonal curves or polygons) with each consisting of segments with the same color. For FPVD, we present an improved algorithm with a running time of O(n log2 n). Our algorithm has better performance and is simpler than the best previously known O(n log2 n)-time algorithm.