Class Solution
Hard
A transformation sequence from word beginWord
to word endWord
using a dictionary wordList
is a sequence of words beginWord -> s1 -> s2 -> … -> sk
such that:
- Every adjacent pair of words differs by a single letter.
- Every
si
for1 <= i <= k
is inwordList
. Note thatbeginWord
does not need to be inwordList
. sk == endWord
Given two words, beginWord
and endWord
, and a dictionary wordList
, return all the shortest transformation sequences from beginWord
to endWord
, or an empty list if no such sequence exists. Each sequence should be returned as a list of the words [beginWord, s1, s2, …, sk]
.
Example 1:
Input: beginWord = “hit”, endWord = “cog”, wordList = [“hot”,“dot”,“dog”,“lot”,“log”,“cog”]
Output: [[“hit”,“hot”,“dot”,“dog”,“cog”],[“hit”,“hot”,“lot”,“log”,“cog”]]
Explanation: There are 2 shortest transformation sequences: “hit” -> “hot” -> “dot” -> “dog” -> “cog” “hit” -> “hot” -> “lot” -> “log” -> “cog”
Example 2:
Input: beginWord = “hit”, endWord = “cog”, wordList = [“hot”,“dot”,“dog”,“lot”,“log”]
Output: []
Explanation: The endWord “cog” is not in wordList, therefore there is no valid transformation sequence.
Constraints:
1 <= beginWord.length <= 5
endWord.length == beginWord.length
1 <= wordList.length <= 1000
wordList[i].length == beginWord.length
beginWord
,endWord
, andwordList[i]
consist of lowercase English letters.beginWord != endWord
- All the words in
wordList
are unique.
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionjava.util.List
<java.util.List<java.lang.String>> findLadders
(java.lang.String beginWord, java.lang.String endWord, java.util.List<java.lang.String> wordList) Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Constructor Details
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Solution
public Solution()
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Method Details
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findLadders
public java.util.List<java.util.List<java.lang.String>> findLadders(java.lang.String beginWord, java.lang.String endWord, java.util.List<java.lang.String> wordList)
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