Unweighted Geometric Hitting Set for Line-Constrained Disks and Related Problems

Fuente: arXiv
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Autores principales: Liu, Gang, Wang, Haitao
Formato: Preprint
Publicado: 2024
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author Liu, Gang
Wang, Haitao
author_facet Liu, Gang
Wang, Haitao
contents Given a set $P$ of $n$ points and a set $S$ of $m$ disks in the plane, the disk hitting set problem asks for a smallest subset of $P$ such that every disk of $S$ contains at least one point in the subset. The problem is NP-hard. In this paper, we consider a line-constrained version in which all disks have their centers on a line. We present an $O(m\log^2n+(n+m)\log(n+m))$ time algorithm for the problem. This improves the previously best result of $O(m^2\log m+(n+m)\log(n+m))$ time for the weighted case of the problem where every point of $P$ has a weight and the objective is to minimize the total weight of the hitting set. Our algorithm actually solves a more general line-separable problem with a single intersection property: The points of $P$ and the disk centers are separated by a line $\ell$ and the boundary of every two disks intersect at most once on the side of $\ell$ containing $P$.
format Preprint
id arxiv_https___arxiv_org_abs_2407_00331
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Unweighted Geometric Hitting Set for Line-Constrained Disks and Related Problems
Liu, Gang
Wang, Haitao
Computational Geometry
Data Structures and Algorithms
Given a set $P$ of $n$ points and a set $S$ of $m$ disks in the plane, the disk hitting set problem asks for a smallest subset of $P$ such that every disk of $S$ contains at least one point in the subset. The problem is NP-hard. In this paper, we consider a line-constrained version in which all disks have their centers on a line. We present an $O(m\log^2n+(n+m)\log(n+m))$ time algorithm for the problem. This improves the previously best result of $O(m^2\log m+(n+m)\log(n+m))$ time for the weighted case of the problem where every point of $P$ has a weight and the objective is to minimize the total weight of the hitting set. Our algorithm actually solves a more general line-separable problem with a single intersection property: The points of $P$ and the disk centers are separated by a line $\ell$ and the boundary of every two disks intersect at most once on the side of $\ell$ containing $P$.
title Unweighted Geometric Hitting Set for Line-Constrained Disks and Related Problems
topic Computational Geometry
Data Structures and Algorithms
url https://arxiv.org/abs/2407.00331