def isIsomorphic(self, s, t):
return len(set(zip(s, t))) == len(set(s)) and len(set(zip(t, s))) == len(set(t))
1 line in Python

@StefanPochmann What about the case where s and t are the same? The question states "All occurrences of a character must be replaced with another character ". Also would the time complexity be O(n)?
