A Fast 2-Approximation Algorithm for Guarding Orthogonal Terrains

Yangdi Lyu; Alper Üngör

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arXiv · 1605.03271

A Fast 2-Approximation Algorithm for Guarding Orthogonal Terrains

Yangdi Lyu·Alper Üngör

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Abstract

Terrain Guarding Problem(TGP), which is known to be NP-complete, asks to find a smallest set of guard locations on a terrain $T$ such that every point on $T$ is visible by a guard. Here, we study this problem on 1.5D orthogonal terrains where the edges are bound to be horizontal or vertical. We propose a 2-approximation algorithm that runs in O($n \log m$) time, where $n$ and $m$ are the sizes of input and output, respectively. This is an improvement over the previous best algorithm, which is a 2-approximation with O($n^2$) running time.

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BibTeX RIS

Yangdi Lyu, Alper Üngör. 2016-05-17. A Fast 2-Approximation Algorithm for Guarding Orthogonal Terrains. https://arxiv.org/abs/1605.03271

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