First Unique Character Index | Dataford Interview Questions

Given a string s, return the index of the first character that appears exactly once. If no such character exists, return -1. Implement the solution in Python using an efficient approach based on character frequency counting.

Constraints

1 <= len(s) <= 10^5
s contains only lowercase English letters
Return -1 if no character appears exactly once

Function Signature

def first_unique_char(s):

Your question is First Unique Character Index. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Constraints

1 <= len(s) <= 10^5
s contains only lowercase English letters
Return -1 if no character appears exactly once

Function Signature

def first_unique_char(s):

Your question is First Unique Character Index. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.