Huffman.Encodingpptx Variable length coding
- 1. Huffman Coding Prepared By: Mr. Zeeshan Mubeen (Senior Lecturer, RSCI) Unit No. 3
- 2. Huffman Coding • Huffman Coding is a famous Greedy Algorithm. • It is used for the lossless compression of data. • It uses variable length encoding. • It assigns variable length code to all the characters. • The code length of a character depends on how frequently it occurs in the given text. • The character which occurs most frequently gets the smallest code. • The character which occurs least frequently gets the largest code. • It is also known as Huffman Encoding.
- 3. Major Steps in Huffman Coding- • There are two major steps in Huffman Coding- 1. Building a Huffman Tree from the input characters. 2. Assigning code to the characters by traversing the Huffman Tree.
- 6. Huffman Tree Step-01: • Create a leaf node for each character of the text. • Leaf node of a character contains the occurring frequency of that character. Step-02: • Arrange all the nodes in increasing order of their frequency value. Step-03: • Considering the first two nodes having minimum frequency, • Create a new internal node. • The frequency of this new node is the sum of frequency of those two nodes. • Make the first node as a left child and the other node as a right child of the newly created node.
- 7. PRACTICEPROBLEMBASEDONHUFFMANCODING- Characters Frequencies a 10 e 15 i 12 o 3 u 4 s 13 T 1 A file contains the following characters with the frequencies as shown. If Huffman Coding is used for data compression, determine
- 9. Step-03:
- 10. Step-04:
- 11. Step-05:
- 12. Step-06
- 13. Step-07:
- 14. Following this rule, the Huffman Code for each character is- •a = 111 •e = 10 •i = 00 •o = 11001 •u = 1101 •s = 01 •t = 11000
- 15. Fix length Vs Huffman code Charac ters Freque ncies Fix length code Cost a 10 000 30 e 15 001 45 i 12 010 36 o 3 011 9 u 4 100 12 s 13 101 39 t 1 110 3 =174 Charact ers Freq uenci es Huffman code Cost a 10 111 30 e 15 10 30 i 12 00 24 o 3 11001 15 u 4 1101 16 s 13 01 26 t 1 11000 5 =146