Question: Huffman encoding and algorithm with example
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  • Huffman encoding is an entropy encoding algorithm developed by David A Huffman that is widely used as lossless data comparison technique.

  • The Huffman coding algorithm uses a variable-length code table to encode a source character, where the variable-length code table is derived in a particular way based on the estimated probability of occurrence for each possible value of the source character.

  • The algorithm works by creating a binary tree of nodes that are stored in a regular array.

  • The size of this array depends on the number of nodes in the tree.

  • A node can either be a leaf node or an internal node. initially, all the nodes in the tree are at the leaf level and store the source character and its frequency of occurrence.

  • While the internal nodes are used to store the weight and contains links to ots child nodes, the external node contains the actual character.

  • Conventionally , a '0' represents following the left child and a '1' represents following the right child.

  • A finished tree has n leaf nodes will have n - 1 internal nodes.

Algorithm:

Step 1: create a leaf node for each character, add the character and its weight or frequency of occurrence to the priority queue.

Step 2 : Repeat step 3 and 5 while the total number of nodes in the queue is greater than 1.

Step 3: Remove 2 nodes that have the lowest weight (or highest priority) and with weight equal to the sum of the 2 nodes weight.

step 4: Add the newly created node to the queue.

Example: Creating Huffman tree for "Maharashtra"

Frequency.

m = 01

a = 04

h = 02

r = 01

s = 01

t = 01

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Huffman code for "Maharashtra" = 01011101110011011101000011

renu • 146 views
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modified 5 months ago  • written 5 months ago by gravatar for RB RB ♦♦ 110
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