code: def diff_commonSuffix(self, text1, text2):
      
      # Quick check for common null cases.
      if not text1 or not text2 or text1[-1] != text2[-1]:
        return 0
      # Binary search.
      # Performance analysis: https://neil.fraser.name/news/2007/10/09/
      pointermin = 0
      pointermax = min(len(text1), len(text2))
      pointermid = pointermax
      pointerend = 0
      while pointermin < pointermid:
        if (text1[-pointermid:len(text1) - pointerend] ==
            text2[-pointermid:len(text2) - pointerend]):
          pointermin = pointermid
          pointerend = pointermin
        else:
          pointermax = pointermid
        pointermid = (pointermax - pointermin) // 2 + pointermin
      return pointermid
docs: Determine the common suffix of two strings.
  
      Args:
        text1: First string.
        text2: Second string.
  
      Returns:
        The number of characters common to the end of each string.