Reducing a target interval to a few exact queries

J. Nederlof, E.J. Leeuwen, van, G.R.J. Zwaan, van der

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

18 Citations (Scopus)
1 Downloads (Pure)


Many combinatorial problems involving weights can be formulated as a so-called ranged problem. That is, their input consists of a universe U, a (succinctly-represented) set family F¿2U , a weight function ¿:U¿¿¿{1,…,N}, and integers 0¿=¿l¿=¿u¿=¿8. Then the problem is to decide whether there is an X¿F such that l¿=¿¿¿ e¿¿¿X ¿(e)¿=¿u. Well-known examples of such problems include Knapsack, Subset Sum, Maximum Matching, and Traveling Salesman. In this paper, we develop a generic method to transform a ranged problem into an exact problem (i.e. a ranged problem for which l¿=¿u). We show that our method has several intriguing applications in exact exponential algorithms and parameterized complexity, namely: In exact exponential algorithms, we present new insight into whether Subset Sum and Knapsack have efficient algorithms in both time and space. In particular, we show that the time and space complexity of Subset Sum and Knapsack are equivalent up to a small polynomial factor in the input size. We also give an algorithm that solves sparse instances of Knapsack efficiently in terms of space and time. In parameterized complexity, we present the first kernelization results on weighted variants of several well-known problems. In particular, we show that weighted variants of Vertex Cover and Dominating Set, Traveling Salesman, and Knapsack all admit polynomial randomized Turing kernels when parameterized by |U|. Curiously, our method relies on a technique more commonly found in approximation algorithms.
Original languageEnglish
Title of host publicationMathematical Foundations of Computer Science (37th International Symposium, MFCS 2012, Bratislava, Slovakia, August 27-31, 2012. Proceedings)
EditorsB. Rovan, V. Sassone, P. Widmayer
Place of PublicationBerlin
ISBN (Print)978-3-642-32588-5
Publication statusPublished - 2012
Externally publishedYes
Event37th International Symposium on Mathematical Foundations of Computer Science (MFCS 2012) - Bratislava, Slovakia
Duration: 27 Aug 201231 Aug 2012
Conference number: 37

Publication series

NameLecture Notes in Computer Science
ISSN (Print)0302-9743


Conference37th International Symposium on Mathematical Foundations of Computer Science (MFCS 2012)
Abbreviated titleMFCS 2012


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