,
Yakov Nekrich
Creative Commons Attribution 4.0 International license
In the orthogonal skyline range counting (resp. reporting) problem we store the set of points P in a data structure so that for any query range Q the number of points (resp. the list of all points) on the skyline of Q∩ P can be found efficiently. In this paper we study two-dimensional range counting and reporting problems in the case when the query range is bounded on three sides. We describe a linear-space data structure that answers top-open three-sided skyline counting queries in O(log log N) time, where N is the number of points stored in the data structure. We also show that bottom-open three-sided skyline counting queries are as difficult as general four-sided queries and any data structure that uses O(Nlog^c N) space for a constant c requires Ω(log N/log log N) time to answer such queries. Next, we turn to skyline color range queries. In this variant of the problem each point in P is assigned a color and we must count (resp. report) the distinct colors of point on the skyline of Q∩ P. We describe an O(N)-space data structure that answers top-open three-sided color counting queries in O(log N/log log N) time. Finally, we study top-open three-sided skyline color reporting in the EM model and describe a data structure that uses linear space and answers queries in O(k/B+1) I/Os where k is the number of colors on the skyline. This is the first external-memory data structure with optimal query cost and space usage for this problem.
@InProceedings{kushwaha_et_al:LIPIcs.SWAT.2026.27,
author = {Kushwaha, Suruchi and Nekrich, Yakov},
title = {{New Results on Three-Sided Skyline Range Counting and Reporting}},
booktitle = {20th Scandinavian Symposium on Algorithm Theory (SWAT 2026)},
pages = {27:1--27:14},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-421-5},
ISSN = {1868-8969},
year = {2026},
volume = {370},
editor = {Fraigniaud, Pierre},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SWAT.2026.27},
URN = {urn:nbn:de:0030-drops-260631},
doi = {10.4230/LIPIcs.SWAT.2026.27},
annote = {Keywords: Data Structures, Range Searching, Skyline Queries}
}