5장/모음_사전.java

import java.util.ArrayList;
import java.util.List;
    
public class Solution {
    private static final char[] CHARS = "AEIOU".toCharArray();
    
    private List<String> generate(String word) {
        List<String> words = new ArrayList<>();
        words.add(word);
    
        if (word.length() == 5) return words;
    
        for (char c : CHARS) {
            words.addAll(generate(word + c));
        }
        return words;
    }
    
    public int solution(String word) {
        return generate("").indexOf(word);
    }
}