Constant-Factor Approximation for TSP with Disks

TL;DR

This paper introduces the first constant-factor approximation algorithm for the traveling salesman problem with disks in the plane, using a reduction to a geometric hitting set problem, advancing solutions for convex bodies.

Contribution

It presents the first constant-ratio approximation for TSP with disks, connecting TSPN to geometric hitting set problems, and broadening applicability to convex bodies.

Findings

Achieves constant-factor approximation for TSP with disks

Reduces TSPN to a geometric hitting set problem

Establishes a new connection between TSPN and hypergraph hitting sets

Abstract

We revisit the traveling salesman problem with neighborhoods (TSPN) and present the first constant-ratio approximation for disks in the plane: Given a set of $n$ disks in the plane, a TSP tour whose length is at most $O(1)$ times the optimal can be computed in time that is polynomial in $n$. Our result is the first constant-ratio approximation for a class of planar convex bodies of arbitrary size and arbitrary intersections. In order to achieve a $O(1)$-approximation, we reduce the traveling salesman problem with disks, up to constant factors, to a minimum weight hitting set problem in a geometric hypergraph. The connection between TSPN and hitting sets in geometric hypergraphs, established here, is likely to have future applications.