Unary code also sometimes called thermometer code is a type of entropy encoding. It is a lossless data compression technique with application in Golomb codes.
Unary representation of a natural number n is n ones followed by a zero. For example, unary code for 6 will be 6 ones followed by a zero which is 1111110
Example:
Input: 5 Output: 111110 result has 5 ones followed by a 0 Input: 1 Output: 10 result has 1 one followed by a 0
Approach:
- For encoding: take an empty list then append N times 1 and 0 in the last then convert it into string and print the result.
- For decoding: Take a given string and count number of 1’s into it and then print the result.
Example 1: Unary representation of a natural number.
Python3
# Unary code encodingN = 8A = []for i in range(N): A.append(1) A.append(0)B = [str(k) for k in A]C = "".join(B)print("Unary code for", N, 'is', C) |
Output:
Unary code for 8 is 111111110
Time Complexity: O(n)
Auxiliary Space: O(n)
Example 2: Decimal representation of an unary code.
Python3
# Unary code decodingcode = "111111110"count = 0for i in code: if i == "1": count += 1 print("decoded number is :", count) |
Output:
decoded number is : 8
Time Complexity: O(n)
Auxiliary Space: O(1)
