Is unique

1class Solution:
2    def isUnique(self, s):
3        # return self.withSet(s)
4        return self.sorting(s)
5
6    def withSet(self, s):
7        if len(s) > 128: return False
8        seen = set()
9        for c in s:
10            if c in seen: return False
11            seen.add(c)
12        return True
13
14    def sorting(self, s):
15        if len(s) > 128: return False
16        s.sort()
17        for i in range(len(s)):
18            if i > 0 and s[i - 1] == s[i]: return False
19        
20        return True