def isUnique(chars):
    charMap = [False] * 128
    for char in chars:
        if charMap[ord(char)]:
            return False
        else:
            charMap[ord(char)] = True
    return True

c6af37ef695dbc1d28de1ad3a18b2fe227bde3a6
<mask token>

def isUnique(chars):
    charMap = [False] * 128
    for char in chars:
        if charMap[ord(char)]:
            return False
        else:
            charMap[ord(char)] = True
    return True
