README.md

Non-Repeating Character

Problem Description

Implement a function that takes a string and returns the first character that does not appear twice or more. Example:

• "abacc" -> 'b' ('a' appears twice, and so does 'c')
• "xxyzx" -> 'y' ('y' and 'z' are non-repeating characters, and 'y' appears first)

If there is no non-repeating character, return None or null.

Solution

I've written an implementation that determines the solution in O(n) time complexity, where n is the number of characters in the given string.

• JavaScript
  • Solution
  • JS Test File
  • CodeSandbox
• Python