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.

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:

  • 11 \leq s.length 103\leq 10^{3}

  • Only lowercase English letters are accepted.

  • There are no spaces in the string.

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