word to word

Question:

For each word, you can get a list of neighbor words by calling getWords(String), find all the paths from word1 to word2.

public class Solution {
    List<List<String>> finalList = new ArrayList<>();

    public static void main(String[] args) {
        Solution s = new Solution();
        System.out.println(s.getPath("face", "book"));
    }

    public List<List<String>> getPath(String s, String e) {
        List<String> list = new ArrayList<String>();
        helper(s, e, list, new HashSet<String>());
        return finalList;
    }

    public void helper(String s, String e, List<String> list, Set<String> set) {
        if (set.contains(s) || (list.size() != 0 && list.get(list.size() - 1).equals(e))) return;
        list.add(s);
        set.add(s);

        if (s.equals(e)) {
            finalList.add(new ArrayList<String>(list));
        }

        List<String> dicts = getWords(s);
        for (String str : dicts) {
            helper(str, e, list, set);
        }

        list.remove(s);
        set.remove(s);
    }

    public List<String> getWords(String str) {
        List<String> list1 = new ArrayList<String>();

        if (str.equals("face")) {
            list1.add("foce");
            list1.add("fack");
        } else if (str.equals("foce")) {
            list1.add("face");
            list1.add("fook");
        } else if (str.equals("fack")) {
            list1.add("fook");
            list1.add("faok");
        } else if (str.equals("fook")) {
            list1.add("fack");
            list1.add("book");
        } else if (str.equals("faok")) {
            list1.add("foce");
            list1.add("book");
        }
        return list1;
    }
}