Find first non-repeating character

Q: Find first non-repeating character

This is a Coding & Algorithms interview question from Walmart Labs for Machine Learning Engineer roles. View the full question and solution on PracHub.

Q: How do I approach Coding & Algorithms interview questions?

Coding & Algorithms questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master coding & algorithms interviews.

Question

Loading...

Given a string s, return the first character that appears exactly once in the string (i.e., the leftmost non-repeating character).

If no such character exists, return an empty string (or a sentinel like "" ).

Examples

Input: "leetcode" → Output: "l"
Input: "aabb" → Output: ""

Constraints

1 ≤ len(s) ≤ 1e5
s contains standard ASCII letters/digits/punctuation (you may assume ASCII for counting).

Find first non-repeating character

Examples

Constraints

Comments (0)