Overlaying simply connected planar subdivisions in linear time

Abstract

We present an algorithm which computes the overlay Π ∪Π Πg of two simply connected planar subdivisionsΠg and Πg; we assume that Πg (resp. Πg) and all its components are colored in blue (resp. green). The algorithm runs in O(n + k) time and space, where n denotes the total number of edges of Πg and Πg and k the number of intersections between blue and green edges.