Computing Partitions of Rectilinear Polygons with Minimum Stabbing Number
The stabbing number of a partition of a rectilinear polygon P into rectangles is the maximum number of rectangles stabbed by any axis-parallel line segment contained in P. We consider the problem of finding a rectangular partition with minimum stabbing number for a given rectilinear polygon P. First, we impose a conforming constraint on partitions: every vertex of every rectangle in the partition must lie on the polygon’s boundary. We show that finding a conforming rectangular partition of minimum stabbing number is NP-hard for rectilinear polygons with holes. We present a rounding method based on a linear programming relaxation resulting in a polynomial-time 2-approximation algorithm. We give an O(nlogn)-time algorithm to solve the problem exactly when P is a histogram (some edge in P can see every point in P) with n vertices. Next we relax the conforming constraint and show how to extend the first linear program to achieve a polynomial-time 2-approximation algorithm for the general problem, improving the approximation factor achieved by Abam, Aronov, de Berg, and Khosravi (ACM SoCG 2011).
Unable to display preview. Download preview PDF.
- 1.Abam, M.A., Aronov, B., de Berg, M., Khosravi, A.: Approximation algorithms for computing partitions with minimum stabbing number of rectilinear and simple polygons. In: Proc. ACM SoCG, pp. 407–416 (2011)Google Scholar