MissingWords

 private static String[] missingWords(String s, String t) {
        List<String> missingWordsList = new ArrayList<>();

        String[] sSplit = s.split("\\s+");
        String[] tSplit = t.split("\\s+");

        int indexS = 0;
        int indexT = 0;

        while (indexS < sSplit.length && indexT < tSplit.length){
            if(sSplit[indexS].equals(tSplit[indexT])){
                indexT++;
            }
            else {
                missingWordsList.add(sSplit[indexS]);
            }

            indexS++;
        }

        for (int i = indexS; i < sSplit.length; i++) {
            missingWordsList.add(sSplit[i]);
        }

        String[] returnArray = new String[missingWordsList.size()];

        missingWordsList.toArray(returnArray);

        return returnArray;
    }