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In computer science and information theory, a Huffman code is a particular type of optimal prefix code that is commonly used for lossless data compression.The process of finding or using such a code is Huffman coding, an algorithm developed by David A. Huffman while he was a Sc.D. student at MIT, and published in the 1952 paper "A Method for the Construction of Minimum-Redundancy Codes".
The optimal length-limited Huffman code will encode symbol i with a bit string of length h i. The canonical Huffman code can easily be constructed by a simple bottom-up greedy method, given that the h i are known, and this can be the basis for fast data compression. [2]
Since a canonical Huffman codebook can be stored especially efficiently, most compressors start by generating a "normal" Huffman codebook, and then convert it to canonical Huffman before using it. In order for a symbol code scheme such as the Huffman code to be decompressed, the same model that the encoding algorithm used to compress the source ...
Second and third bits: Encoding method used for this block type: 00: A stored (a.k.a. raw or literal) section, between 0 and 65,535 bytes in length; 01: A static Huffman compressed block, using a pre-agreed Huffman tree defined in the RFC; 10: A dynamic Huffman compressed block, complete with the Huffman table supplied; 11: Reserved—don't use.
Adaptive Huffman coding (also called Dynamic Huffman coding) is an adaptive coding technique based on Huffman coding. It permits building the code as the symbols are being transmitted, having no initial knowledge of source distribution, that allows one-pass encoding and adaptation to changing conditions in data.
BTLZ is an LZ78-based algorithm that was developed for use in real-time communications systems (originally modems) and standardized by CCITT/ITU as V.42bis. When the trie-structured dictionary is full, a simple re-use/recovery algorithm is used to ensure that the dictionary can keep adapting to changing data. A counter cycles through the ...
compressed file (often tar zip) using Lempel-Ziv-Welch algorithm 1F A0 ␟⍽ 0 z tar.z Compressed file (often tar zip) using LZH algorithm 2D 68 6C 30 2D-lh0-2 lzh Lempel Ziv Huffman archive file Method 0 (No compression) 2D 68 6C 35 2D-lh5-2 lzh Lempel Ziv Huffman archive file Method 5 (8 KiB sliding window) 42 41 43 4B 4D 49 4B 45 44 49 53 ...
In Computers and Intractability [8]: 226 Garey and Johnson list the bin packing problem under the reference [SR1]. They define its decision variant as follows. Instance: Finite set of items, a size () + for each , a positive integer bin capacity , and a positive integer .