Find all shortest transformation sequences from beginWord to endWord, changing one letter at a time.
Sample Input:
"hit", "cog", ["hot","dot","dog","lot","log","cog"]
Sample Output:
[["hit","hot","dot","dog","cog"],["hit","hot","lot","log","cog"]]
Hints
Hint 1
Use BFS to find shortest paths
Hint 2
Build adjacency list of word transformations
Hint 3
Track paths during BFS traversal
