How to cover a point set with a V-shape of minimum width (Conference Paper)

摘要

A balanced V-shape is a polygonal region in the plane contained in the union of two crossing equal-width strips. It is delimited by two pairs of parallel rays that emanate from two points x, y, are contained in the strip boundaries, and are mirror-symmetric with respect to the line xy. The width of a balanced V-shape is the width of the strips. We first present an O(~(n2)logn) time algorithm to compute, given a set of n points P, a minimum-width balanced V-shape covering P. We then describe a PTAS for computing a (1+ε)-approximation of this V-shape in time O((n/ε)logn+(n/ ε3 ~(/2)) ~(log2)(1/ε)). A much simpler constant-factor approximation algorithm is also described.