2026-07-21T12:28:43Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:17679 2024-03-06T11:00:17Z ddc:004 open_access

An Approximation Algorithm for Distance-Constrained Vehicle Routing on Trees Dufay, Marc Mathieu, Claire Zhou, Hang vehicle routing distance constraint approximation algorithms trees In the Distance-constrained Vehicle Routing Problem (DVRP), we are given a graph with integer edge weights, a depot, a set of n terminals, and a distance constraint D. The goal is to find a minimum number of tours starting and ending at the depot such that those tours together cover all the terminals and the length of each tour is at most D. The DVRP on trees is of independent interest, because it is equivalent to the "virtual machine packing" problem on trees studied by Sindelar et al. [SPAA'11]. We design a simple and natural approximation algorithm for the tree DVRP, parameterized by ε > 0. We show that its approximation ratio is α + ε, where α ≈ 1.691, and in addition, that our analysis is essentially tight. The running time is polynomial in n and D. The approximation ratio improves on the ratio of 2 due to Nagarajan and Ravi [Networks'12]. The main novelty of this paper lies in the analysis of the algorithm. It relies on a reduction from the tree DVRP to the bounded space online bin packing problem via a new notion of "reduced length". Schloss Dagstuhl – Leibniz-Zentrum für Informatik Marc Dufay and Claire Mathieu and Hang Zhou 2023 Is Part Of LIPIcs, Volume 254, 40th International Symposium on Theoretical Aspects of Computer Science (STACS 2023) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.STACS.2023.27 urn:nbn:de:0030-drops-176794 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2023.27 eng https://creativecommons.org/licenses/by/4.0/legalcode