2026-08-25T17:34:07Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:27266 2026-08-25T13:18:20Z ddc:004 open_access

Approximation Algorithms for the Traveling Thief Problem Eube, Jan Luo, Kelin Röglin, Heiko Sturm, Sarah Traveling Thief Problem Traveling Salesperson Problem Knapsack Problem Approximation Algorithms Bi-objective optimization The Traveling Thief Problem (TTP) combines the Traveling Salesperson Problem with the Knapsack Problem. In this problem, a finite metric space is given, and at each location an item with some profit and weight is placed. An agent seeks to collect a subset of the items. To do so, the agent must decide which items to collect and to determine a cyclic tour visiting the corresponding locations. While collecting an item yields its profit as a reward, the agent’s speed decreases as more weight is picked up. The problem involves two competing objectives: maximizing the total profit of the collected items and minimizing the travel time of the tour. While many heuristics and exact algorithms (with a non-polynomial running time) have been developed, no approximation algorithms are known for any variant of the TTP. We aim at computing an (α₁,α₂)-approximate Pareto set that, for every solution, contains another solution collecting at least a 1/(α₁) fraction of its profit while requiring at most α₂ times its travel time. Our main result is an algorithm that calculates a (9 + ε,9 + ε)-approximate Pareto set in polynomial time. We also consider the setting in which the set of items to be collected is given in advance, so that the agent only has to compute a tour through the corresponding locations that minimizes the total travel time. This is the so-called Weighted TSP. For this setting, we present a (2e + ε)-approximation algorithm. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Jan Eube and Kelin Luo and Heiko Röglin and Sarah Sturm 2026 Is Part Of LIPIcs, Volume 388, 34th Annual European Symposium on Algorithms (ESA 2026) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.ESA.2026.130 urn:nbn:de:0030-drops-272668 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2026.130 eng https://creativecommons.org/licenses/by/4.0/legalcode