Given a string s consisting only of the characters 'a' and 'b', return true if every 'a' appears before every 'b' in the string. Otherwise, return false.
Constraints:
s.length
s[i] is either 'a' or 'b'
Given a string s consisting only of the characters 'a' and 'b', return true if every 'a' appears before every 'b' in the string. Otherwise, return false.
Constraints:
s.length
s[i] is either 'a' or 'b'