Title
Solving the 2-Disjoint Connected Subgraphs Problem Faster than 2n
Abstract
The 2-Disjoint Connected Subgraphs problem, given a graph along with two disjoint sets of terminals Z 1, Z 2, asks whether it is possible to find disjoint sets A 1, A 2, such that Z 1⊆ A 1, Z 2⊆ A 2 and A 1, A 2 induce connected subgraphs. While the naive algorithm runs in O (2 n n O (1)) time, solutions with complexity of form O ((2 ) n ) have been found only for special graph classes (van 't Hof et al. in Theor. Comput. Sci. 410(47---49):4834---4843, 2009 ; Paulusma and van Rooij in Theor. Comput. Sci. 412(48):6761---6769, 2011 ). In this paper we present an O (1.933 n ) algorithm for 2-Disjoint Connected Subgraphs in general case, thus breaking the 2 n barrier. As a counterpoise of this result we show that if we parameterize the problem by the number of non-terminal vertices, it is hard both to speed up the brute-force approach and to find a polynomial kernel.
Year
DOI
Venue
2014
10.1007/s00453-013-9796-x
Algorithmica
Keywords
Field
DocType
Exact algorithms,2,n,barrier,2-Disjoint Connected Subgraphs,Kernelization,Exponential Time Hypothesis
Kernelization,Discrete mathematics,Combinatorics,Disjoint sets,Vertex (geometry),Polynomial kernel,Connected component,Strongly connected component,Mathematics,Speedup,Exponential time hypothesis
Journal
Volume
Issue
ISSN
70
2
0178-4617
Citations 
PageRank 
References 
3
0.40
22
Authors
4
Name
Order
Citations
PageRank
Marek Cygan155640.52
michal pilipczuk240351.93
Michał Pilipczuk3231.74
jakub onufry wojtaszczyk41549.48