임시

import java.util.*;
import java.lang.*;
class Solution {
    
    ArrayList<List<String>> answer = new ArrayList<>();
    ArrayList<List<String>> realAnswer = new ArrayList<>();
    List<String> wordList;
    int lowSize = Integer.MAX_VALUE;
    
    public List<List<String>> findLadders(String beginWord, String endWord, List<String> wordList) {
        
        this.wordList = wordList;
        
        dfs(beginWord,endWord,new ArrayList<String>());
        
        for(List<String> temp : answer)
            if(temp.size()==lowSize) realAnswer.add(temp);
        
        
        return realAnswer;
        
    }
    
    
    public void dfs(String beginWord, String endWord,ArrayList<String> list){
        list.add(beginWord);
        if(beginWord.equals(endWord)){

            answer.add(list);
            lowSize = Math.min(lowSize,list.size());
            return;
        }
        
       
        for(String word : wordList){
            if(!list.contains(word)&&getEditDistance(beginWord,word)==1){
                ArrayList<String> clone = new ArrayList(list);
                dfs(word,endWord,clone);
            }
        }
    }
    
    public int getEditDistance(String s1,String s2){
        int[][] distance = new int[s1.length()+1][s2.length()+1];
        
        for(int i=0; i<=s1.length(); i++){
            distance[i][0] = i;
            distance[0][i] = i;
        }
        
        for(int i=0; i<s1.length(); i++){
            for(int j=0; j<s2.length(); j++){
                if(i==j){
                    if(s1.charAt(i)==s2.charAt(j))
                        distance[i+1][j+1] = distance[i][j];
                    else
                        distance[i+1][j+1] = distance[i][j] + 1;
                }else{
                    distance[i+1][j+1] = Math.min(distance[i][j+1],distance[i+1][j])+1;
                }
            }
        }
        
        
        return distance[s1.length()][s2.length()];
    }
}

포스팅용 소스코드 저장 용 (시간 초과 코드)