"""
字符串相加
"""


class Solution:
    def addStrings(self, num1: str, num2: str) -> str:
        """
        双指针
        :param num1:
        :param num2:
        :return:
        """
        res = ""
        i, j, carry = len(num1) - 1, len(num2) - 1, 0
        while i >= 0 or j >= 0:
            n1 = int(num1[i]) if i >= 0 else 0
            n2 = int(num2[j]) if j >= 0 else 0
            all = n1 + n2 + carry
            carry = all // 10
            res = str(all % 10) + res
            i -= 1
            j -= 1
        return "1" + res if carry else res


if __name__ == '__main__':
    result = Solution().addStrings("11", "123")
    print(result)