2. Huffman’s Algorithm

3. What is Huffman’s Algorithm?
 Huffman’s algorithm is a method for building
an extended binary tree with minimum weighted path
length from a set of given weights
It is technique for compressing data.

4. What is Huffman’s Algorithm?
Huffman coding is a lossless data compression
algorithm. The idea is to assign variable-length
codes to input characters, lengths of the
assigned codes are based on the frequencies of
corresponding characters.
The most frequent character gets the smallest
code and the least frequent character gets the
largest code.

5. Tree Construction Rules
• There are mainly two major parts in Huffman Coding
1) Build a Huffman Tree from input characters.
2) Traverse the Huffman Tree and assign codes to
characters
•
1.
2.
3.
Steps to build Huffman Tree
Create a leaf node for each unique character
Extract two nodes with the minimum frequency
Create a new internal node with frequency equal to the
sum of the two nodes frequencies.
4. 4. Repeat steps#2 and #3 until the heap contains only
one node. The remaining node is the root node and the
tree is complete

6. Huffman Tree Construction
A
3
C
E
H
I
5
8
2
7

7. Huffman Tree Construction
A
H
3
2
5
C
5
E
8
I
7

8. Huffman Tree Construction
E
H
3
2
C
5
5
10
I
8
A
7

9. Huffman Tree Construction
E
H
3
I
8
A
7
2
C
15
5
5
10

10. Huffman Tree Construction
A
H
3
2
1
5
C
E
I
5
0
8
7
0
1
1
0
15
10
0
1
25
E
I
C
A
H
=
=
=
=
=
00
01
10
111
110