TY: JOUR
T1 - Computing a visibility polygon using few variables
A1 - Barba, Luis
A1 - Korman, Matias
A1 - Langerman, Stefan
A1 - Silveira, Rodrigo
N2 - We present several algorithms for computing the visibility polygon of a simple polygon P of n vertices (out of which r are reflex) from a viewpoint inside P, when P resides in read-only memory and only few working variables can be used. The first algorithm uses a constant number of variables, and outputs the vertices of the visibility polygon in O(nr¯) time, where r¯ denotes the number of reflex vertices of P that are part of the output. Whenever we are allowed to use O(s) variables, the running time decreases to O(nr2s+nlog2r) (or O(nr2s+nlogr) randomized expected time), where s?O(logr). This is the first algorithm in which an exponential space-time trade-off for a geometric problem is obtained.
UR - https://ria.ua.pt/handle/10773/21926
Y1 - 2014
PB - Elsevier