,
Ajaykrishnan E S
,
Daniel Lokshtanov
,
Anikait Mundhra
,
Thomas Schibler
,
Xiaoyang Xu
,
Jie Xue
Creative Commons Attribution 4.0 International license
In the Rectangle Stabbing problem, input is a set R of axis-parallel rectangles and a set L of axis-parallel lines in the plane. The task is to find a minimum size set L^* ⊆ L such that for every rectangle R ∈ R there is a line 𝓁 ∈ L^* such that 𝓁 intersects R. Gaur et al. [Journal of Algorithms, 2002] gave a polynomial time 2-approximation algorithm, while Dom et al. [WALCOM 2009] and Giannopoulos et al. [EuroCG 2009] independently showed that, assuming FPT ≠ W[1], there is no algorithm with running time f(k)(|L||R|)^O(1) that determines whether there exists an optimal solution with at most k lines. We give the first parameterized approximation algorithm for the problem with a ratio better than 2. In particular we give an algorithm that given R, L, and an integer k runs in time k^O(k)(|L||R|)^O(1) and either correctly concludes that there does not exist a solution with at most k lines, or produces a solution with at most 7k/4 lines. We complement our algorithm by showing that unless FPT = W[1], the Rectangle Stabbing problem does not admit a (5/4-ε)-approximation algorithm running in f(k)(|L||R|)^O(1) time for any function f and ε > 0.
@InProceedings{chu_et_al:LIPIcs.ESA.2026.69,
author = {Chu, Huairui and E S, Ajaykrishnan and Lokshtanov, Daniel and Mundhra, Anikait and Schibler, Thomas and Xu, Xiaoyang and Xue, Jie},
title = {{Parameterized Approximation of Rectangle Stabbing}},
booktitle = {34th Annual European Symposium on Algorithms (ESA 2026)},
pages = {69:1--69:20},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-445-1},
ISSN = {1868-8969},
year = {2026},
volume = {388},
editor = {Bille, Philip and Pettie, Seth and Storandt, Sabine},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2026.69},
URN = {urn:nbn:de:0030-drops-272056},
doi = {10.4230/LIPIcs.ESA.2026.69},
annote = {Keywords: rectangle stabbing, parameterized algorithms, approximation algorithms, computational geometry, parameterized approximation complexity, geometric hitting set, lower bounds}
}