Hard · Graphs

Word Ladder

Given beginWord, endWord and a list of words of the same length, return the number of words in the shortest sequence from beginWord to endWord in which consecutive words differ in exactly one letter and every word after beginWord is in the list, or 0 if no such sequence exists.

Examples

Example 1

{
  "beginWord": "hit",
  "endWord": "cog",
  "wordList": ["hot", "dot", "dog", "lot", "log", "cog"]
}

Output: ladder 5

Example 2

{
  "beginWord": "hit",
  "endWord": "cog",
  "wordList": ["hot", "dot", "dog", "lot", "log"]
}

Output: ladder 0

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