A New Algorithm for Euclidean Shortest Paths in the Plane

Document Type

Conference Paper

Author ORCID Identifier

Haitao Wang https://orcid.org/0000-0001-8134-7409

Journal/Book Title/Conference

ACM SIGACT Symposium on Theory of Computing 2021

Publisher

Association for Computing Machinery

Publication Date

6-15-2021

Award Number

NSF, Division of Computing and Communication Foundations (CCF) 2005323

Funder

NSF, Division of Computing and Communication Foundations (CCF)

First Page

975

Last Page

988

Abstract

Given a set of pairwise disjoint polygonal obstacles in the plane, finding an obstacle-avoiding Euclidean shortest path between two points is a classical problem in computational geometry and has been studied extensively. Previously, Hershberger and Suri [SIAM J. Comput. 1999] gave an algorithm of O(nlogn) time and O(nlogn) space, where n is the total number of vertices of all obstacles. Recently, by modifying Hershberger and Suri’s algorithm, Wang [SODA 2021] reduced the space to O(n) while the runtime of the algorithm is still O(nlogn). In this paper, we present a new algorithm of O(n+hlogh) time and O(n) space, provided that a triangulation of the free space is given, where h is the number of obstacles. Our algorithm builds a shortest path map for a source point s, so that given any query point t, the shortest path length from s to t can be computed in O(logn) time and a shortest s-t path can be produced in additional time linear in the number of edges of the path.

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