new_contents: class Solution:
      # @return an integer
      def lengthOfLongestSubstring(self, s):
          start, maxlen = 0, 0
          dict = {s[i]: -1 for i in range(len(s))}
          for i in range(len(s)):
              if dict[s[i]] != -1:
                  while start <= dict[s[i]]:
                      dict[s[start]] = -1
                      start += 1
              if i - start + 1 > maxlen: maxlen = i - start + 1
              dict[s[i]] = i
          return maxlen
  
subject: Create LongSubWRC_001.py