@Test
    public void testEasy6() throws Exception {
        String start = "hit";
        String end = "abc";
        String[] words = {};
        Set<String> dict = Utils.stringArrayToSet(words);

        WordLadderII wordLadderII = new WordLadderII();
        List<List<String>> result = wordLadderII.findLadders(start, end, dict);

        Utils.printListListString(result);
    }