,
Qizheng He
,
Jie Xue
Creative Commons Attribution 4.0 International license
Let X be a set of points in ℝ² and 𝒪 be a set of geometric objects in ℝ², where |X| + |𝒪| = n. We study the problem of computing a minimum subset 𝒪^* ⊆ 𝒪 that encloses all points in X. Here a point x ∈ X is enclosed by 𝒪^* if it lies in a bounded connected component of ℝ²∖(⋃_{O ∈ 𝒪^*} O). We propose two algorithmic frameworks to design polynomial-time approximation algorithms for the problem. The first framework is based on sparsification and min-cut, which results in O(1)-approximation algorithms for unit disks, unit squares, etc. The second framework is based on LP rounding, which results in an O(α(n)log n)-approximation algorithm for segments, where α(n) is the inverse Ackermann function, and an O(log n)-approximation algorithm for disks.
@InProceedings{chan_et_al:LIPIcs.SoCG.2024.35,
author = {Chan, Timothy M. and He, Qizheng and Xue, Jie},
title = {{Enclosing Points with Geometric Objects}},
booktitle = {40th International Symposium on Computational Geometry (SoCG 2024)},
pages = {35:1--35:15},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-316-4},
ISSN = {1868-8969},
year = {2024},
volume = {293},
editor = {Mulzer, Wolfgang and Phillips, Jeff M.},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2024.35},
URN = {urn:nbn:de:0030-drops-199802},
doi = {10.4230/LIPIcs.SoCG.2024.35},
annote = {Keywords: obstacle placement, geometric optimization, approximation algorithms}
}