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arXiv 1010.4502cs.DScs.CG
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在线方形包装

Online Square Packing

Sandor P. Fekete, Tom Kamphans, Nils Schweer

摘要:

我们在线分析了填充正方形的问题:给定一个宽度为1的半无限长带和一个未知的边长为[0,1]的正方形序列,它们从上面到达,一次一个。目标是在这些物品到达时将其打包,最大限度地减少由此产生的高度。就像经典的俄罗斯方块游戏一样,每个方块必须沿着一条无碰撞的路径移动到最终目的地。此外,我们在运动(方块永远不会向上移动)和位置(任何最终目的地必须从下面得到支持)中考虑了重力。类似的问题之前已经考虑过;之前最好的结果是Azar和Epstein,他们在没有重力的情况下给出了一个4-竞争算法(即,有可能让正方形“悬在空中”)基于货架包装的想法:正方形被分配到不同的水平高度,允许分析,这让人想起一些装箱的论点。我们应用几何分析来建立左下启发式的竞争因子3.5,并提出34/13=2.615......竞争算法

英文摘要:

We analyze the problem of packing squares in an online fashion: Given a semi-infinite strip of width 1 and an unknown sequence of squares of side length in [0,1] that arrive from above, one at a time. The objective is to pack these items as they arrive, minimizing the resulting height. Just like in the classical game of Tetris, each square must be moved along a collision-free path to its final destination. In addition, we account for gravity in both motion (squares must never move up) and position (any final destination must be supported from below). A similar problem has been considered before; the best previous result is by Azar and Epstein, who gave a 4-competitive algorithm in a setting without gravity (i.e., with the possibility of letting squares "hang in the air") based on ideas of shelf-packing: Squares are assigned to different horizontal levels, allowing an analysis that is reminiscent of some bin-packing arguments. We apply a geometric analysis to establish a competitive factor of 3.5 for the bottom-left heuristic and present a 34/13=2.615...-competitive algorithm.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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