ARC Colloquium: Ian Munro - University of Waterloo

Event Details

Dani Denton
denton at cc dot gatech dot edu



Summary Sentence: Klaus 1116 West at 1 pm

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Algorithms & Randomness Center (ARC)

Ian Munro – University of Waterloo

Monday, February 1, 20116

Klaus 1116 West - 1:00 pm

(Refreshments will be served in Klaus 2222 at 2 pm)

Optimal Search Trees with 2-way Comparisons

This talk is about finding a polynomial time algorithm that you probably thought was known almost a half century ago, but it wasn’t. The polynomial time algorithm is still rather slow and requires a lot of space to solve, so we also look at extremely good and fast approximate solutions. More specifically …
In 1971, Knuth gave an O(n2)-time algorithm for the now classic problem of finding an optimal binary search tree. Knuth’s algorithm works only for search trees based on 3-way comparisons, but most modern programming languages and computers support only 2-way comparisons (<, = and >). Until this work, the problem of finding an optimal search tree using 2-way comparisons remained open — polynomial time algorithms were known only for restricted variants. We solve the general case, giving

(i)  an O(n4)-time algorithm and

(ii) a linear time algorithm that gives a tree with expected search cost within 2 comparisons of the optimal.

This is joint work with Marek Chrobak, Mordecai Golin, and Neal E. Young.

Additional Information

In Campus Calendar

ARC, College of Computing, School of Computer Science

Invited Audience
Undergraduate students, Faculty/Staff, Public, Graduate students
Algorithm and Randomness Center, ARC, Computational Complexity, Computational Learning Theory, Georgia Tech
  • Created By: Dani Denton
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  • Created On: Jan 14, 2016 - 10:10am
  • Last Updated: Apr 13, 2017 - 5:17pm