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What and Who

Optimal Prefix Codes with Fewer Distinct Codeword Lengths are Easier to Construct

Amr Elmasry
Max-Planck-Institut für Informatik - D1
AG1 Mittagsseminar (own work)
AG 1, AG 4, RG1, MMCI, AG 3, AG 5, SWS  
AG Audience
English

Date, Time and Location

Friday, 23 October 2009
13:00
30 Minutes
E1 4
024
Saarbrücken

Abstract

A new method for constructing minimum-redundancy prefix codes is described. This method does not explicitly build a Huffman tree; instead it uses a property of optimal codes to find the codeword length of each weight. The running time of the algorithm is shown to be $O(n k)$, which is asymptotically faster than Huffman's algorithm when $k=o(\log{n})$, where $n$ is the number of weights and $k$ is the number of distinct codeword lengths.

We also sketch a matching lower bound of $\Omega(n k)$ for any such construction algorithm, indicating that our algorithm is asymptotically optimal in terms of $n$ and $k$.

Contact

Amr Elmasry
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Tags, Category, Keywords and additional notes

Prefix codes - Huffman tree - Distribution-sensitive algorithms

Amr Elmasry, 10/12/2009 14:56 -- Created document.