天题系列：Word Ladder II

乍一看还真以为和1 一样，呵呵

当然不是啦

Given two words (start and end), and a dictionary, find all shortest transformation sequence(s) from start to end, such that:

1. Only one letter can be changed at a time
2. Each intermediate word must exist in the dictionary

For example,

Given:
start = "hit"
end = "cog"
dict = ["hot","dot","dog","lot","log"]

Return

  [
    ["hit","hot","dot","dog","cog"],
    ["hit","hot","lot","log","cog"]
  ]

 

Note:

• All words have the same length.
• All words contain only lowercase alphabetic characters.

ref “ http://www.1point3acres.com/bbs/thread-51646-1-1.html 上面 iostreamin写的”

我决定不写啦