Implementing an algorithm to determine if a string has all unique characters [closed]

Answer 1

Solution 1:

def is_unique(string):
  if len(string) > 128:
    return False

  unique_tracker = [False] * 128
  for char in string:
    if unique_tracker[ord(char)] == False:
      unique_tracker[ord(char)] = True
    else:
      return False
  return True

Solution 2:

def is_unique_bit(string):
  if len(string) > 128:
  return False

  unique_tracker = 0
  for char in string:
    ascii_val = ord(char)
    if (unique_tracker & (1 << ascii_val)) > 0:
      return False
    unique_tracker |= (1 << ascii_val)
  return True