479. Unique Character Count Parity

Given a string s, determine if the number of unique characters in the string is even or odd. Return the string "even" if the count of unique characters is even, and "odd" if it is odd.

Example:
Input: s = "banana"
Output: "odd"
Explanation: The unique characters are 'b', 'a', 'n'. The count is 3, which is odd.

Run this challenge interactively in Python or JavaScript when the app loads.