Primal-Dual 2-Approximation Algorithm for the Monotonic Multiple Depot Heterogeneous Traveling Salesman Problem

Authors S. Rathinam, R. Ravi, J. Bae, K. Sundar

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Author Details

S. Rathinam
  • Texas A & M University, College Station, TX 77843, USA
R. Ravi
  • Carnegie Mellon University, Pittsburgh, PA 15213, USA
J. Bae
  • Michigan Technological University, Houghton, MI 49931, USA
K. Sundar
  • Los Alamos Laboratory, NM 87545, USA

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S. Rathinam, R. Ravi, J. Bae, and K. Sundar. Primal-Dual 2-Approximation Algorithm for the Monotonic Multiple Depot Heterogeneous Traveling Salesman Problem. In 17th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 162, pp. 33:1-33:13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


We study a Multiple Depot Heterogeneous Traveling Salesman Problem (MDHTSP) where the cost of the traveling between any two targets depends on the type of the vehicle. The travel costs are assumed to be symmetric, satisfy the triangle inequality, and are monotonic, i.e., the travel costs between any two targets monotonically increases with the index of the vehicles. Exploiting the monotonic structure of the travel costs, we present a 2-approximation algorithm based on the primal-dual method.

Subject Classification

ACM Subject Classification
  • Theory of computation → Routing and network design problems
  • Approximation Algorithm
  • Heterogeneous Traveling Salesman Problem
  • Primal-dual Method


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