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Determine if a string has all unique characters

Input : A string
Output : Boolean

Clarifications :

• Is the input string ASCII or Unicode ?
  • If ASCII then we need storage size of 128 bits

Logic :

• Iterate over entire string
• If string size greater than 128 characters (total ASCII characters) then return false.
• Iterate over the string one character at a time,
  • For each character find if there is another similar character in the string after it.
  • If there is one then return false
• Else return true.

Time complexity : O(n) ; where n is the string length
Space complexity : O(1) ; constant

Solution :

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