Maintenance of geometric extrema ∈
Maintenance of geometric extrema ∈
复制标题
几何极值的维护
DOI:
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发表时间:
1991
期刊:
影响因子:
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通讯作者:
S. Suri
中科院分区:
文献类型:
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作者:
D. Dobkin;S. Suri
Let <italic>S</italic> be a set, <italic>f</italic>: <italic>S</italic>×<italic>S</italic>→<italic>R</italic><supscrpt>+</supscrpt> a bivariate function, and <italic>f</italic>(<italic>x</italic>,<italic>S</italic>) the <italic>maximum</italic> value of <italic>f</italic>(<italic>x</italic>,<italic>y</italic>) over all elements <italic>y</italic><inline-equation><f>∈</f></inline-equation><italic>S</italic>. We say that <italic>f</italic> is <italic>decomposable</italic> with respect with the maximum if <italic>f</italic>(<italic>x</italic>,<italic>S</italic>) = max {<italic>f</italic>(<italic>x</italic>,<italic>S</italic><subscrpt>1</subscrpt>),<italic>f</italic>(<italic>x</italic>,<italic>S</italic><subscrpt>2</subscrpt>),…,<italic>f</italic>(<italic>x</italic>,<italic>S<subscrpt>k</subscrpt></italic>)} for any decomposition <italic>S</italic> = μ<subscrpt><italic>i</italic>=1</subscrpt><supscrpt><italic>i</italic>=<italic>k</italic></supscrpt><italic>S<subscrpt>i</subscrpt></italic>. Computing the maximum (minimum) value of a decomposable function is inherent in many problems of computational geometry and robotics. In this paper, a general technique is presented for updating the maximum (minimum) value of a decomposable function as elements are inserted into and deleted from the set <italic>S</italic>. Our result holds for a <italic>semi-online</italic> model of dynamization: When an element is inserted, we are told how long it will stay. Applications of this technique include efficient algorithms for <italic>dynamically</italic> computing the diameter or closest pair of a set of points, minimum separation among a set of rectangles, smallest distance between a set of points and a set of hyperplanes, and largest or smallest area (perimeter) retangles determined by a set of points. These problems are fundamental to application areas such as robotics, VLSI masking, and optimization.