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A message is made up entirely of characters from the set X = {P,Q,R,S,T}. The table of probabilities for each of the characters is shown below:
Character Probability P 0.22 Q 0.34 R 0.17 S 0.19 T 0.08 Total 1.00
If a message of 100 characters over X is encoded using Huffman coding, then the expected length of the encoded message in bits is ________.
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- 125
- 225
- 525
- 121
Correct Option: B
By using haffman tree :
So, number of bit required for each alphabet:
T = 3 bit, R = 3 bit, Q = 2 bit, S = 2 bit, P = 2 bit
Then, average length per character is = (number of bits * frequency of occurance of each alphabets)
= 3 * 0.08 + 3 * 0.17 + 2 * 0.34 + 2 * 0.19 + 2 * 0.22 = 2.25 bits
And, average length for 100 character = 2.25 * 100 = 225 bits.
Hence, 225 bits is correct answer
