,
Esther Ezra
,
Micha Sharir
Creative Commons Attribution 4.0 International license
We study various nearest-neighbor searching problems involving points, lines, segments and triangles in ℝ³. Among many results, we present a linear-size data structure for answering nearest-neighbor queries with lines amid n points in ℝ³, in O^*(n^{1/2}) time per query (where the O^*(⋅) notation hides subpolynomial factors). Our solution is based on parametric search, where the problem is reduced to range emptiness queries amid points in ℝ³ with cylindrical queries. For the latter problem we show that reporting all k points lying inside a cylinder query costs an additional term of O(k). We also study setups where both data and query objects are lines, segments, or triangles, and obtain improved solutions for the two extreme regimes of (near-)linear storage and of fast query time. These results also yield tradeoff bounds, where the cost of a query depends on the storage allocated to the structure. This work is a continuation of a recent work by the authors [Pankaj K. Agarwal et al., 2024].
@InProceedings{agarwal_et_al:LIPIcs.ESA.2026.34,
author = {Agarwal, Pankaj K. and Ezra, Esther and Sharir, Micha},
title = {{Triangle Nearest-Neighbor Searching in 3-Space}},
booktitle = {34th Annual European Symposium on Algorithms (ESA 2026)},
pages = {34:1--34:22},
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.2026.34},
URN = {urn:nbn:de:0030-drops-271709},
doi = {10.4230/LIPIcs.ESA.2026.34},
annote = {Keywords: line-point nearest neighbors, range searching, vertical decomposition in 3-space, test sets}
}