2D knapsack: Packing squares

  • Authors:
  • Yan Lan;György Dósa;Xin Han;Chenyang Zhou;Attila Benko

  • Affiliations:
  • Dalian Neusoft Institute of Information, China;Department of Mathematics, University of Pannonia, Veszprém, Hungary;School of Software of Dalian University of Technology, China;School of Software of Dalian University of Technology, China;Department of Mathematics, University of Pannonia, Veszprém, Hungary

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2013

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Abstract

In this paper, we study a two-dimensional knapsack problem: packing squares as many as possible into a unit square. Our results are the following: (i)we propose an algorithm called IHS (Increasing Height Shelf), and prove that the packing is optimal if in an optimal packing there are at most 5 squares, and this upper bound is sharp; (ii)if all the squares have side length at most 1k, we propose a simple and fast algorithm with an approximation ratio k^2+3k+2k^2 in time O(nlogn); (iii)we give an EPTAS for the problem, where the previous result in Jansen and Solis-Oba (2008) [16] is a PTAS, not an EPTAS. However our approach does not work on the previous model of Jansen and Solis-Oba (2008) [16], where each square has an arbitrary weight.