415.add-strings.py

#
# @lc app=leetcode id=415 lang=python3
#
# [415] Add Strings
#

# @lc code=start
class Solution:
    def addStrings(self, num1: str, num2: str) -> str:
        res = ""
        carry = 0
        i, j = len(num1) - 1, len(num2) - 1
        while i >= 0 or j >= 0 or carry:
            digit1 = ord(num1[i]) - ord('0') if i >= 0 else 0
            digit2 = ord(num2[j]) - ord('0') if j >= 0 else 0
            digit_sum = digit1 + digit2 + carry
            carry = digit_sum // 10
            res = chr(digit_sum % 10 + ord('0')) + res
            i -= 1
            j -= 1
        return res
# @lc code=end