new_contents: # Time:  O(min(a, b))
  # Space: O(1)
  
  # Given a group of two strings, you need to find the longest uncommon subsequence of this group of two strings.
  # The longest uncommon subsequence is defined as the longest subsequence of one of these strings
  # and this subsequence should not be any subsequence of the other strings.
  #
  # A subsequence is a sequence that can be derived from one sequence
  # by deleting some characters without changing the order of the remaining elements.
  # Trivially, any string is a subsequence of itself and an empty string is a subsequence of any string.
  #
  # The input will be two strings, and the output needs to be the length of the longest uncommon subsequence.
  # If the longest uncommon subsequence doesn't exist, return -1.
  #
  # Example 1:
  # Input: "aba", "cdc"
  # Output: 3
  # Explanation: The longest uncommon subsequence is "aba" (or "cdc"), 
  # because "aba" is a subsequence of "aba", 
  # but not a subsequence of any other strings in the group of two strings. 
  # Note:
  #
  # Both strings' lengths will not exceed 100.
  # Only letters from a ~ z will appear in input strings.
  
  class Solution(object):
      def findLUSlength(self, a, b):
          """
          :type a: str
          :type b: str
          :rtype: int
          """
          if a == b:
              return -1
          return max(len(a), len(b))
  
subject: Create longest-uncommon-subsequence-i.py