Greedy Methodology

1. Huffman Tree Coding
Greedy Technique
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Dr. P. Subathra
Prof/ IT
KAMARAJ College of Engg. & Tech
(AUTONOMOUS)
Madurai

2. Huffman Tree Coding
• Encoding
– In computer technology, encoding is the process of putting a
sequence of characters into a special format for transmission
or storage purposes.
• Code Word
– The special format that represents each character is called as
the code word
• Fixed Length Encoding
– fixed-length encoding that assigns to each symbol a bit string
of the same length m
– Eg. ASCII codes
• Variable Length Encoding
– Variable-length encoding, which assigns codewords of
different lengths to different symbols
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3. Huffman Tree Coding
• Encoding
– In computer technology, encoding is the process of putting a
sequence of characters into a special format for transmission
or storage purposes.
• Code Word
– The special format that represents each character is called as
the code word
• Fixed Length Encoding
– fixed-length encoding that assigns to each symbol a bit string
of the same length m
– Eg. ASCII codes
• Variable Length Encoding
– Variable-length encoding, which assigns codewords of
different lengths to different symbols
3

4. Huffman Tree Coding
• Encoding
– In computer technology, encoding is the process of putting a
sequence of characters into a special format for transmission
or storage purposes.
• Code Word
– The special format that represents each character is called as
the code word
• Fixed Length Encoding
– fixed-length encoding that assigns to each symbol a bit string
of the same length m
– Eg. ASCII codes
• Variable Length Encoding
– Variable-length encoding, which assigns codewords of
different lengths to different symbols
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5. Huffman Tree Coding
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6. Huffman Tree Coding
Frequency of Occurrence of English Alphabets
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7. Huffman Tree Coding
• Encoding
– In computer technology, encoding is the process of putting a
sequence of characters into a special format for transmission
or storage purposes.
• Code Word
– The special format that represents each character is called as
the code word
• Fixed Length Encoding
– fixed-length encoding that assigns to each symbol a bit string
of the same length m
– Eg. ASCII codes
• Variable Length Encoding
– Variable-length encoding, which assigns codewords of
different lengths to different symbols
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8. Huffman Tree Coding
• Variable-length encoding assigns codewords of different lengths to
different symbols
• Eg.
E 1
A 10
P 101
Q 1010
• How to decode: 110101 ?
• How can we tell how many bits of an encoded text represent the
first ?
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9. Huffman Tree Coding
• We can limit ourselves to the so-called prefix-free (or simply
prefix) codes.
• In a prefix code, no codeword is a prefix of a codeword of
another symbol.
• Eg.
E 1
A 01
P 100
Q 101
• How to decode: 10101101 ?
• 1 01 01 101  E A A Q
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10. Huffman Tree Coding
Consider the five-symbol alphabet { A, B, C, D, _ }
with the following occurrence frequencies in a text
made up of these symbols:
Create a Huffman Tree and Generate the Huffman
Code.
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11. Huffman Tree Coding
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12. Huffman Tree Coding
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13. Huffman Tree Coding
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14. Huffman Tree Coding
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15. Huffman Tree Coding
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16. Huffman Tree Coding
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17. Huffman Tree Coding
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18. Huffman Tree Coding
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19. Huffman Tree Coding
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20. Huffman Tree Coding
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21. Huffman Tree Coding
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22. Huffman Tree Coding
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23. Huffman Tree Coding
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24. Huffman Tree Coding
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25. Huffman Tree Coding
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26. Huffman Tree Coding
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27. Huffman Tree Coding
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28. Huffman Tree Coding
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Character Code
A
B
C
D
-

29. Huffman Tree Coding
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Character Code
A 11
B
C
D
-

30. Huffman Tree Coding
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Character Code
A 11
B 100
C
D
-

31. Huffman Tree Coding
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Character Code
A 11
B 100
C 00
D
-

32. Huffman Tree Coding
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Character Code
A 11
B 100
C 00
D 01
-

33. Huffman Tree Coding
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Character Code
A 11
B 100
C 00
D 01
- 101

34. Huffman Tree Coding
Encode: “DAD CAB”
D A D C A B
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Character Code
A 11
B 100
C 00
D 01
- 101

35. Huffman Tree Coding
Encode: “DAD CAB”
D A D C A B
100
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Character Code
A 11
B 100
C 00
D 01
- 101

36. Huffman Tree Coding
Encode: “DAD CAB”
D A D C A B
100 11
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Character Code
A 11
B 100
C 00
D 01
- 101

37. Huffman Tree Coding
Encode: “DAD CAB”
D A D C A B
100 11 01
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Character Code
A 11
B 100
C 00
D 01
- 101

38. Huffman Tree Coding
Encode: “DAD CAB”
D A D C A B
100 11 01 101
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Character Code
A 11
B 100
C 00
D 01
- 101

39. Huffman Tree Coding
Encode: “DAD CAB”
D A D C A B
100 11 01 101 00
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Character Code
A 11
B 100
C 00
D 01
- 101

40. Huffman Tree Coding
Encode: “DAD CAB”
D A D C A B
100 11 01 101 00 11
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Character Code
A 11
B 100
C 00
D 01
- 101

41. Huffman Tree Coding
Encode: “DAD_CAB”
D A D _ C A B
100 11 01 101 00 11 100
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Character Code
A 11
B 100
C 00
D 01
- 101

42. Huffman Tree Coding
Decode: 10011011010011100
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Character Code
A 11
B 100
C 00
D 01
- 101

43. Huffman Tree Coding
Decode: 100 11 01 101 00 11 100
B
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Character Code
A 11
B 100
C 00
D 01
- 101

44. Huffman Tree Coding
Decode: 100 11 01 101 00 11 100
B A
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Character Code
A 11
B 100
C 00
D 01
- 101

45. Huffman Tree Coding
Decode: 100 11 01 101 00 11 100
B A D
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Character Code
A 11
B 100
C 00
D 01
- 101

46. Huffman Tree Coding
Decode: 100 11 01 101 00 11 100
B A D _
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Character Code
A 11
B 100
C 00
D 01
- 101

47. Huffman Tree Coding
Decode: 100 11 01 101 00 11 100
B A D _ C
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Character Code
A 11
B 100
C 00
D 01
- 101

48. Huffman Tree Coding
Decode: 100 11 01 101 00 11 100
B A D _ C A
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Character Code
A 11
B 100
C 00
D 01
- 101

49. Huffman Tree Coding
Decode: 100 11 01 101 00 11 100
B A D _ C A B
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Character Code
A 11
B 100
C 00
D 01
- 101

50. Huffman Tree Coding
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