A Simple Linear-Time Algorithm for Computing the Centroid and Canonical Form of a Plane Graph and Its Applications

Abstract

We present a simple linear-time algorithm for computing the topological centroid and the canonical form of a plane graph. Although the targets are restricted to plane graphs, it is much simpler than the linear-time algorithm by Hopcroft and Wong for determination of the canonical form and isomorphism of planar graphs. By utilizing a modified centroid for outerplanar graphs, we present a linear-time algorithm for a geometric version of the maximum common connected edge subgraph (MCCES) problem for the special case in which input geometric graphs have outerplanar structures, MCCES can be obtained by deleting at most a constant number of edges from each input graph, and both the maximum degree and the maximum face degree are bounded by constants.