static class State{

String word;

int cnt;

public State(String word, int cnt){

this.word = word;

this.cnt = cnt;

}

}

public int solution(String begin, String target, String[] words) {

int answer = 0;

// words에 target이 없으면 0

if(!isInclude(target, words)) return answer;

// BFS로 words에 있는 단어중 target 찾기

int N = words.length;

boolean[] visited = new boolean[N];

Queue<State> q = new LinkedList<>();

q.add(new State(begin, 0));

while(!q.isEmpty()){

State now = q.poll();

if(now.word.equals(target)){

answer = now.cnt;

break;

}

for(int i=0; i<N; i++){

if(!visited[i]){

int wc = 0;

for(int j=0; j<words[i].length(); j++){

if(words[i].charAt(j) == now.word.charAt(j)) wc++;

}

if(now.word.length() - wc == 1){

visited[i] = true;

q.add(new State(words[i], now.cnt+1));

}

}

}

}

return answer;

}

public static boolean isInclude(String target, String[] words){

for(String word: words){

if(target.equals(word)){

return true;

}

}

return false;

}

}