Given two words (start and end), and a dictionary, find the length of shortest transformation sequence from start to end, such that:
- You must change exactly one character in every transformation
- Each intermediate word must exist in the dictionary
start = "hit" end = "cog" dict = ["hot","dot","dog","lot","log"]
As one shortest transformation is
"hit" -> "hot" -> "dot" -> "dog" -> "cog",
return its length
Note that we account for the length of the transformation path instead of the number of transformation itself.
- Return 0 if there is no such transformation sequence.
- All words have the same length.
- All words contain only lowercase alphabetic characters.