EnsambleWords

public boolean ensambleWords(String str, Set<String> dict) {
  return str.equals("") ? false : ensambleWords(str, 0, dict);
}

public boolean ensambleWords(String str, int start, Set<String> dict) {
  if (start == str.length()) {
    return false;
  } else {
    for (int end = start; end < str.length(); end++) {
      if (dict.contains(str.substring(start, end + 1)) &&
          ensambleWords(str, start + 1, dict)) {
            return true;
      }
      return false;
    }
  }
}