Package g0101_0200.s0127_word_ladder
Class Solution
java.lang.Object
g0101_0200.s0127_word_ladder.Solution
127 - Word Ladder.<p>Hard</p>
<p>A <strong>transformation sequence</strong> from word <code>beginWord</code> to word <code>endWord</code> using a dictionary <code>wordList</code> is a sequence of words <code>beginWord -> s<sub>1</sub> -> s<sub>2</sub> -> … -> s<sub>k</sub></code> such that:</p>
<ul>
<li>Every adjacent pair of words differs by a single letter.</li>
<li>Every <code>s<sub>i</sub></code> for <code>1 <= i <= k</code> is in <code>wordList</code>. Note that <code>beginWord</code> does not need to be in <code>wordList</code>.</li>
<li><code>s<sub>k</sub> == endWord</code></li>
</ul>
<p>Given two words, <code>beginWord</code> and <code>endWord</code>, and a dictionary <code>wordList</code>, return <em>the <strong>number of words</strong> in the <strong>shortest transformation sequence</strong> from</em> <code>beginWord</code> <em>to</em> <code>endWord</code><em>, or</em> <code>0</code> <em>if no such sequence exists.</em></p>
<p><strong>Example 1:</strong></p>
<p><strong>Input:</strong> beginWord = “hit”, endWord = “cog”, wordList = [“hot”,“dot”,“dog”,“lot”,“log”,“cog”]</p>
<p><strong>Output:</strong> 5</p>
<p><strong>Explanation:</strong> One shortest transformation sequence is “hit” -> “hot” -> “dot” -> “dog” -> cog", which is 5 words long.</p>
<p><strong>Example 2:</strong></p>
<p><strong>Input:</strong> beginWord = “hit”, endWord = “cog”, wordList = [“hot”,“dot”,“dog”,“lot”,“log”]</p>
<p><strong>Output:</strong> 0</p>
<p><strong>Explanation:</strong> The endWord “cog” is not in wordList, therefore there is no valid transformation sequence.</p>
<p><strong>Constraints:</strong></p>
<ul>
<li><code>1 <= beginWord.length <= 10</code></li>
<li><code>endWord.length == beginWord.length</code></li>
<li><code>1 <= wordList.length <= 5000</code></li>
<li><code>wordList[i].length == beginWord.length</code></li>
<li><code>beginWord</code>, <code>endWord</code>, and <code>wordList[i]</code> consist of lowercase English letters.</li>
<li><code>beginWord != endWord</code></li>
<li>All the words in <code>wordList</code> are <strong>unique</strong>.</li>
</ul>
-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionintladderLength(String beginWord, String endWord, List<String> wordDict)
-
Constructor Details
-
Solution
public Solution()
-
-
Method Details
-
ladderLength
-