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Solution: First Unique Character in a String

Understand how to find the first unique character in a string by tracking character frequency with a hash map. Learn to implement an efficient solution with O(n) time complexity and constant space usage. This lesson helps you grasp tracking methods for string problems common in coding interviews.

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 ...