> For the complete documentation index, see [llms.txt](https://nataliekung.gitbook.io/solutions/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nataliekung.gitbook.io/solutions/word_ladder/java.md).

# Java

public class Solution {

public int ladderLength(String beginWord, String endWord, Set\<String> wordList) {

Queue\<String> q=new LinkedList\<String>();

Set\<String> visited=new HashSet\<String>();

q.offer(beginWord);

visited.add(beginWord);

int distance=1;

int count=1;

while(count>0){

while(count>0){

//当前Level

char\[] s=q.poll().toCharArray();

for(int i=0;i\<s.length;i++){

char temp = s\[i];

for(char c='a';c<'z';c++){

if(temp==c) continue;

s\[i]=c;

String str= new String(s);

if(str.equals(endWord)) return distance+1;

if(str!=beginWord && wordList.contains(str)&&!visited.contains(str)){

q.offer(str);

visited.add(str);

}

}

s\[i]=temp;

}

count--;

}

//计算下一个level

distance++;

count=q.size();

}

return 0;

}

}