2025-08-03 10:19:10 +0000 UTC

class Solution:
    def reformat(self, s: str) -> str:
        res, digits, al = [""], [], []
        for char in s:
            if char.isalpha():
                al.append(char)
            else:
                digits.append(char)
            while digits and al:
                res.extend((digits.pop(), al.pop()))
        if digits:
            res.append(digits.pop())
        elif al:
            res[0] = al.pop()
        if digits or al:
            return ""
        return "".join(res)