LZW Compression

What

Use dictionary to compress a ASCII encoded text.
Work best with repeated words.

How

Input: text: A sequence of characters in the ASCII character set.
Output: A sequence of indices into a dictionary.

1. For each character c in the ASCII character set:
   1. A. Insert c into the dictionary at the index equal to c’s numeric code in ASCII.
2. Set s to the first character from text.
3. While text is not exhausted, do the following:
   1. A. Take the next character from text, and assign it to c.
   2. B. If s c is in the dictionary, then set s to s c.
   3. C. Otherwise (s c is not yet in the dictionary), do the following:
      1. i. Output the index of s in the dictionary.
      2. ii. Insert s c into the next available entry in the dictionary.
      3. iii. Set s to the single-character string c.
4. Output the index of s in the dictionary.

Why