74. First Non-Repeating Character
Challenge1000 ms256 MBSolved by 0%
Read one line and print the first character that appears exactly once in it.
If every character repeats, print None.
The comparison is case-sensitive, and spaces count as characters.
Constraints - The line has between 1 and 100000 characters. - Printable ASCII only.
Input
A single line of text.
Output
Print the first character that appears exactly once, or None if every character repeats.
Inputswiss
Outputw
Notehas the first unique character in the middle
Inputaabb
OutputNone
Notehas every character repeating
Hints
Four rungs, in order. The last two open once you have submitted an attempt. A wrong one counts.
Hint 1Where to start
Hint 2The approachOpen hint 1 first. This one carries on from it.
Hint 3PseudocodeOpen hint 2 first. This one carries on from it.
Hint 4Full solutionOpen hint 3 first. This one carries on from it.