Word Ladder II

Given a start word, end word, and a list of dictionary words, find all shortest transformation sequences where each step changes exactly one letter, and each intermediate word must be in the dictionary.

Examples
Input: ["hit","cog",["hot","dot","dog","lot","log","cog"]]
Output: [["hit","hot","dot","dog","cog"],["hit","hot","lot","log","cog"]]
Hints

Word Ladder II

Given a start word, end word, and a list of dictionary words, find all shortest transformation sequences where each step changes exactly one letter, and each intermediate word must be in the dictionary.