,
Stefan Kratsch
Creative Commons Attribution 4.0 International license
In the d-Clique Packing problem, given a graph G and an integer t, we need to decide whether G contains a set of t pairwise vertex-disjoint cliques of size d each. This generalizes Triangle Packing and it is NP-complete for all d ≥ 3. For each such d, we show how to solve the problem in n^𝒪(k^{d-1}) time where k is the clique-width of the graph (with a k-expression of G given in the input). We complement this by showing that, assuming the Exponential-Time Hypothesis (ETH), there is no algorithm that solves the problem in n^o(k^{d-1}) time for any fixed d ≥ 3, already for the special case of seeking a partition into cliques of size d. Our proof also entails W[1]-hardness of d-Clique Packing (and d-Clique Partitioning) parameterized by clique-width for each d ≥ 3. Our work continues a series of results on ETH-tight bounds for fundamental graph problems started by Fomin et al. (SICOMP 2010+2014) who obtained tight bounds for Max-Cut and Edge Dominating Set.
@InProceedings{bojikian_et_al:LIPIcs.ESA.2026.115,
author = {Bojikian, Narek and Kratsch, Stefan},
title = {{Tight Bounds for Clique-Packing Parameterized by Clique-Width}},
booktitle = {34th Annual European Symposium on Algorithms (ESA 2026)},
pages = {115:1--115:15},
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.2026.115},
URN = {urn:nbn:de:0030-drops-272519},
doi = {10.4230/LIPIcs.ESA.2026.115},
annote = {Keywords: Parameterized complexity, triangle packing, clique packing, clique-width}
}