Solution: First Unique Character in a String

Let's solve the First Unique Character in a String problem using the Knowing What to Track pattern.

We'll cover the following

Statement

For a given string of characters, s, your task is to find the first non-repeating character and return its index. Return −1-1 if there’s no unique character in the given string.

Constraints:

  • 1≤1 \leq s.length ≤103\leq 10^{3}

  • Only lowercase English letters are accepted.

  • There are no spaces in the string.