On the Planar Two-Center Problem and Circular Hulls
On the Planar Two-Center Problem and Circular Hulls
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关于平面二中心问题和圆壳
DOI:
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发表时间:
2020
影响因子:
0.8
通讯作者:
Haitao Wang
中科院分区:
文献类型:
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作者:
Haitao Wang
Given a set S of n points in the Euclidean plane, the two-center problem is to find two congruent disks of smallest radius whose union covers all points of S. Previously, Eppstein (SODA’97) gave a randomized algorithm of O(nlog2n)documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$O(nlog ^2!n)$$end{document} expected time and Chan (CGTA’99) presented a deterministic algorithm of O(nlog2nlog2logn)documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$O(nlog ^2!nlog ^2log n)$$end{document} time. In this paper, we propose an O(nlog2n)documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$O(nlog ^2!n)$$end{document} time deterministic algorithm, which improves Chan’s deterministic algorithm and matches the randomized bound of Eppstein. If S is in convex position, then we solve the problem in O(nlognloglogn)documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$O(nlog nlog log n)$$end{document} deterministic time. Our results rely on new techniques for dynamically maintaining circular hulls under point insertions and deletions, which are of independent interest.