@Test
    public void testWA() throws Exception {
        String[] strs = {"ted", "tex", "red", "tax", "tad", "den", "rex", "pee"};
        Set<String> set = new HashSet<String>();
        Collections.addAll(set, strs);
        List<List<String>> list = wordLadderII.findLadders("red", "tax", set);
        Utils.printStringStringList(list);
    }