Solution: Word Ladder II

Explore how to solve the Word Ladder II problem by identifying all shortest transformation sequences between words. Understand the combined use of BFS to find shortest paths and DFS backtracking to reconstruct all valid sequences. This lesson equips you to efficiently apply graph traversal techniques for word-based transformation challenges in coding interviews.

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Statement
Solution
- Time complexity
- Space complexity

Statement

You are given two words, beginWord and endWord, and a dictionary of words called wordList. Your task is to find all the shortest transformation sequences from beginWord to endWord, such that:

Only one letter can be changed at a time.
Each transformed word must exist in the given wordList.
The transformation sequence must begin with beginWord and end with endWord.

Return all the shortest transformation sequences as a list of lists. If no valid transformation exists, return an empty list.

Constraints:

$1 \leq$ beginWord.length $\leq 5$
endWord.length == beginWord.length
$1 \leq$ wordList.length $\leq 500$ ...