Check If String has All Unique Characters

Objective: Write an algorithm to find out whether in a given string contains all the unique characters. This question has been asked in the Amazon and Microsoft interviews.

Input:  A String

Output: True or false based upon whether string contains all the unique characters or not.

Approach:

Method 1.

When characters are not ASCII but could be anything alphabets or special characters

• Create a boolean array of size 256, and put false at every index.
• Navigate the input string one character at a time, say 'char a'
• Check array position of array[a], if it is false, make it true.
• If it is already true, return false.

Method 2:

Run This Code

Code:

Output

:
Method 1 : Does String ' Sumit_Jain ' has all unique characters :false
Method 1 : Does String ' Sumit ' has all unique characters :true
Method 2 : Does String ' Sumit_Jain ' has all unique characters :false
Method 2 : Does String ' Sumit ' has all unique characters :true

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