Problem H: Edit Step Ladders
An edit step is a transformation from one word x to another
word y such that x and y are words in the dictionary,
and x can be
transformed to y by adding, deleting, or changing one letter.
So the transformation from dig to dog or from
dog to do are both edit steps. An edit step ladder
is a lexicographically ordered sequence of words
w1, w2, ... wn
such that the transformation from wi to wi+1
is an edit step for all i from 1 to n-1.
For a given dictionary, you are to compute the length of the longest
edit step ladder. The input to your program consists of the dictionary -
a set of lower case words in lexicographic order - one per line. No word exceeds
16 letters and there are no more than 25000 words in the dictionary.
The output consists of a single integer, the number of words in the
longest edit step ladder.
Output for Sample Input