CODE EXAMPLE FOR JAVA

missingWords

public static List<String> findWord(String s, String t) {
    HashSet<String> missingWords = new HashSet<>();
    String[] words = s.split(" ");
    for(int i=0; i < words.length; i++) {
        if (!t.contains(words[i])) {
            missingWords.add(words[i]);
        }
    }
    List<String> ans = new ArrayList<String>();
    for (String str: missingWords) {
        ans.add(str);
    }

    return ans;
}