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Determine Whether a Word Transformation Exists

This question evaluates a candidate's ability to model single-character word transformations as a graph/search problem, testing competencies in graph traversal, string manipulation, and state-space connectivity within the Coding & Algorithms domain.

Given a beginWord, an endWord, and a list of valid words wordList, determine whether it is possible to transform beginWord into endWord.

Rules:

Each transformation changes exactly one character.
Every transformed word must exist in wordList.
All words contain only lowercase English letters and have the same length.
Return true if at least one valid transformation sequence exists; otherwise return false.

Example:

Input: beginWord = "hit", endWord = "cog", wordList = ["hot", "dot", "dog", "lot", "log", "cog"]
Output: true

Because one valid sequence is: hit -> hot -> dot -> dog -> cog

You only need to return a boolean value, not the length of the shortest transformation.

Word Transformation Exists

Return whether beginWord can reach endWord by changing one character at a time through wordList words.

Hints

Bucket words by wildcard patterns.
Run BFS from beginWord until endWord is found.