kai08-cn/practice

code for code, practice code

practice

Miller-Rabin algorithm

Program name: genPrime.py

Argument to your program: m

Command line usage of your script: genPrime.py <m>

Output: Output to terminal the value of prime n in decimal (which would take m-bits to represent in binary).

Example: m = 4, the program will output either 11 or 13.

Huffman algorithm

Program name: header.py

Argument to your program: An input text file containing a string str[0 . . . nn1]. It is safe to assume that:

• str consists of ASCII characters (characters are not restricted to be lower case only!).
• There are no line breaks in the input file.

Command line usage of your script: header.py <input text file>

Output format: The output is a text file containing a header for the input string str. The header is a bitstring (see the note above which details how to represent the bits) made up of the following information:

• The number of unique ASCII characters in str encoded using the corresponding Elias ω integer code.
• For each unique character in the text:
  • Encode the unique character using the fixed-length 7-bit ASCII code. (All input characters will have ASCII values < 128).
  • Then encode the length of the Huffman code assigned to that unique character using an Elias ω code.
  • To the above, append the variable-length Huffman codeword assigned to that unique character.

Example：

aacaacabcaba ==> 011110000111110001001000110001101001

Lempel-Ziv-Storer-Szymanski (LZSS) decoder

a variation of the LZ77 algorithm.

Example:

01111000011111000100100011000110100100011111111010011000100100001101111 ==> aacaacabcaba