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First Non-Repeating Character
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First Non-Repeating Character

EasyPython

Problem

Given a string s, return the first character that appears exactly once while preserving the original order of characters. If no such character exists, return an empty string "". The input is a single string, and the output is a single character or an empty string.

Constraints

  • 0 <= len(s) <= 10^5
  • s contains printable characters
  • Return the first unique character based on its original order

Function Signature

def first_non_repeating_char(s):
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