Guarding orthogonal art galleries with sliding cameras

摘要

We study the problem of guarding an orthogonal art gallery with security cameras sliding back and forth along straight tracks. We show that if only vertical (alternatively, horizontal) tracks are allowed, then a solution minimizing the number of tracks can be found in polynomial time, and if both orientations are allowed, then a 2-approximation can be found in polynomial time for x-monotone galleries.