2016 - T1 - WS3 - Central workshop

Collection 2016 - T1 - WS3 - Central workshop

Organisateur(s) Braverman, Mark ; Nazer, Bobak ; Rao, Anup ; Tchamkerten, Aslan
Date(s) 29/02/2016 - 04/03/2016
URL associée https://web.archive.org/web/20221228152147/http://iss.bu.edu/bobak/csnexus//workshopabout.html
00:00:00 / 00:00:00
17 20

The information theoretic lower bound for comparison based sorting is (almost) tight, even when there is an arbitrary known distribution on the input array

De Shay Moran

I will discuss the classical problem of sorting n elements when the input array is drawn from an arbitrary known distribution and the goal is to minimize the expected number of comparisons. I will present a simple variant of insertion sort which provides tight upper bound: If μ is a distribution on permutations on n elements, then one may sort inputs from μ with expected number of comparisons that is at most H(μ)+2n, where H is the entropy function. The algorithm uses less comparisons for more probable inputs: For every permutation π, the algorithm sorts π by using at most log_2(1/Pr_μ(π))+2n comparisons. A lower bound on the expected number of comparisons of H(μ) always holds, and a linear dependence on n is also required. I will also suggest directions for further research. The talk is based on a joint work with Amir Yehudayoff.

Informations sur la vidéo

  • Date de captation 29/02/2016
  • Date de publication 14/03/2016
  • Institut IHP
  • Licence CC BY-NC-ND
  • Format MP4

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