Puzzle instructions:

  Write a program that reads a large list of English words (e.g. from
  /usr/share/dict/words on a unix system) into memory, and then reads
  words from stdin, and prints either the best spelling suggestion, or
  "NO SUGGESTION" if no suggestion can be found. The program should print ">"
  as a prompt before reading each word, and should loop until killed.

  Your solution should be faster than O(n) per word checked, where n is
  the length of the dictionary. That is to say, you can't scan the
  dictionary every time you want to spellcheck a word.

  For example:

  > sheeeeep
  > peepple
  > sheeple

  The class of spelling mistakes to be corrected is as follows:

  Case (upper/lower) errors: "inSIDE" => "inside"
  Repeated letters: "jjoobbb" => "job"
  Incorrect vowels: "weke" => "wake"
  Any combination of the above types of error in a single word should be
  corrected (e.g. "CUNsperrICY" => "conspiracy").

  If there are many possible corrections of an input word, your program
  can choose one in any way you like. It just has to be an English word
  that is a spelling correction of the input by the above rules.

  Final step: Write a second program that *generates* words with spelling
  mistakes of the above form, starting with correctly spelled English words.
  Pipe its output into the first program and verify that there are no
  occurrences of "NO SUGGESTION" in the output.

To Test:
  ./ | ./ > output
  grep NO output