s = "abcdefghijklmnopqrstuvwxyz" def find_words(s): if len(s) < 2: return 0 word_dict = {s[0]:1} max_length = 1 for i in range(1, len(s)): if s[i] in word_dict: word_dict[s[i]] += 1 else: word_dict[s[i]] = 1 # if i == len(s) - 1: # return max_length for j in range(i + 1, len(s)): if s[j] in word_dict: if s[j] == s[i]: max_length = max(max_length, j - i + 1) else: break else: word_dict[s[j]] = 1 if j == len(s) - 1: return max_length return max_length find_words()