1. Madivalappagouda Patil
Huffman coding
Madivalappagouda Patil

2. Introduction used for compressing the data
uses the table of frequencies of occurrence of characters
each character is represented by a binary string
Two ways
Fixed length code
Variable length code

3. Take the characters and their frequencies, and sort this list by increasing frequency
All the characters are vertices of the tree
Take the first 2 vertices from the list and make them children of a vertex having the sum of their frequencies
Insert the new vertex into the sorted list of vertices
If there are at least 2 vertices in the list, fallow the above steps.
Read the Huffman code from the tree

4. The (Real) Basic Algorithm
An Introduction to Huffman Coding
March 21, 2000
The (Real) Basic Algorithm
1. Scan text to be compressed and tally occurrence of all characters.
2.Sort or prioritize characters based on number of occurrences in text.
3.Build Huffman code tree based on prioritized list.
4. Perform a traversal of tree to determine all code words.
5. Scan text again and create new file using the Huffman codes.
CS 102
Mike Scott

5. n=|C|
Q=C
for i=1 to n-1
Z=new tree node
left=(z)=Extract Min(Q)
Right=(z)= Extract Min(Q)
frequency(z)=frequency(x)+frequency(y)
Insert(Q,z)
Return Extract Min(Q)

6. Example

10. Summary
Huffman coding is a technique used to compress files for transmission
Uses statistical coding
more frequently used symbols have shorter code words
Works well for text and fax transmissions
An application that uses several data structures
CS 102

11. Thank you