leetcode-415-字符串相加

题目描述：

第一次提交：

class Solution:
    def addStrings(self, num1: str, num2: str) -> str:
        if len(num1) < len(num2):
            num1,num2 = num2,num1
        num1 = [_ for _ in num1[::-1]]
        num2 = [_ for _ in num2[::-1]] + ['0' for _ in range(len(num1)-len(num2))]
        res = 0
        for i in range(len(num1)):
            temp = int(num1[i]) + int(num2[i])
            res += temp*10**i
        return str(res)

另;

class Solution:
    def addStrings(self, num1: str, num2: str) -> str:
        res = ''
        i,j,carry = len(num1)-1,len(num2)-1,0
        while i>=0 or j>=0:
            n1 = ord(num1[i]) - ord('0') if i>=0 else 0
            n2 = ord(num2[j]) - ord('0') if j>=0 else 0
            temp = n1+n2+carry
            carry = temp//10
            res = str(temp % 10) + res
            i,j = i-1,j-1
        if carry:
            res = '1'+res
        return res