dumbowords Files

Dummy program that takes a string of characters (e.g. str == "asdeqwdrfesatgha") and natural number n
(1 <= n <= length str) and finds all words made from characters from str with length n (checks in a 
dictionary if the current string with length n is a word). Made it to help a friend cheat in a
Android app called "Scrabble" or whatever. Written in Haskell, which I'm still learning. To make it 
more effective I've used a family of trees - one for each letter from the alphabet, a tree represents
all words of the dictionary starting with a given letter. After that given a string the tree either
"recognizes" it as a word and returns the same word or otherwise returns an empty string. This method
is way faster than direct search for a string of the pool (666k strings for n = 6, length str = 12)
in the dictionary (~120k entries). Still a very naive method which can be optimized a lot more but I
did it just for fun.