Huffman Coding by Akas

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HUFFMAN CODING 2010 1 FEASIBILITY STUDY In computer science and information theory , Huffman coding is an entropy encoding algorithm used for lossless data compression . The term refers to the use of a variable-length code table for encoding a source symbol (such as a character in a file) where the variable-length code table has been derived in a particular way based on the estimated probability of occurrence for each possible value of the source symbol. It was developed by David A. Huffman at MIT , and published in the 1952 paper "A Method for the Construction of Minimum-Redundancy Codes". Huffman coding uses a specific method for choosing the representation for each symbol, resulting in a prefix code (sometimes called "prefix-free codes") (that is, the bit string representing some particular symbol is never a prefix of the bit string representing any other symbol) that expresses the most common characters using shorter strings of bits than are used for less common source symbols. Huffman was able to design the most efficient compression method of this type: no other mapping of individual source symbols to unique strings of bits will produce a smaller average output size when the actual symbol frequencies agree with those used to create the code 1.1 History: In 1951, David A. Huffman and his MIT information theory classmates were given the choice of a term paper or a final exam . The professor, Robert M. Fano , assigned a term paper on the problem of finding the most efficient binary code. Huffman, unable to prove any codes were the most efficient, was about to give up and start studying for the final when he hit upon the idea of using a frequency-sorted binary tree and quickly proved this method the most efficient. In doing so, the student outdid his professor, who had worked with information theory inventor Claude Shannon to develop a similar code. B.E COMPUTER ENGINEERING Page 1

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use of data structures in deriving huffman codes for symbols with given frequency

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