2025-08-01 13:33:40 +0000 UTC

class Solution:
    def reverseOnlyLetters(self, s: str) -> str:
        i, j = 0, len(s) - 1
        res = [None] * len(s)
        while i <= j:
            char1, char2 = s[i], s[j]
            if not char1.isalpha():
                res[i] = char1
                i += 1
            elif not char2.isalpha():
                res[j] = char2
                j -= 1
            else:
                res[i], res[j] = char2, char1
                i += 1
                j -= 1
        return "".join(res)