code: private int calcCountSubstringsWords(String str, HashSet<String> words) {
      int wordCount = 0;
      int N = str.length();
      for (int i = 0; i < N - 1; i++)
        for (int j = i + 2; j < N + 1; j++) {
          if (words.contains(str.substring(i, j)))
            wordCount += 1;
        }
      return wordCount;
    }
docs: count all substrings >= 2 chars that are in words