reverse_vowels_of_a_string.py

class Solution:
    def reverseVowels(self, s: str) -> str:
        vowels = set("aeiouAEIOU")
        s = list(s)
        left, right = 0, len(s) - 1

        while left < right:
            if s[left] not in vowels:
                left += 1
                continue
            if s[right] not in vowels:
                right -= 1
                continue
            
            s[left], s[right] = s[right], s[left]
            left += 1
            right -= 1
        return "".join(s)