1343 · 两字符串和

描述
给定两个仅含数字的字符串，你需要返回一个由各个位之和拼接的字符串

A 和 B 是由数字组成的字符串
样例
示例1:
输入:
A = "99"
B = "111"
输出: "11010"
解释: 因为 9 + 1 = 10, 9 + 1 = 10, 0 + 1 = 1,连接之后的结果是 "11010"
示例2:
输入:
A = "2"
B = "321"
输出: "323"
解释: 因为 1 + 2 = 3, 2 + 0 = 2, 3 + 0 = 3,连接之后的结果是 "323"

class Solution:
    """
    @param A: a string
    @param B: a string
    @return: return the sum of two strings
    """
    def SumofTwoStrings(self, A, B):
        A = A[::-1]
        B = B[::-1]
        res = []
        for i in range(min(len(A), len(B))):
            res.append(str(int(A[i]) + int(B[i]))) 
        return A[i+1:][::-1] + B[i+1:][::-1] + "".join(res[::-1])