Leetcode 415. Add Strings

Seawolf

1. Given two non-negative integers num1 and num2 represented as string, return the sum of num1 and num2.
   
2. 
   
3. Note:
   
4. 
   
5. The length of both num1 and num2 is < 5100.
   
6. Both num1 and num2 contains only digits 0-9.
   
7. Both num1 and num2 does not contain any leading zero.
   
8. You must not use any built-in BigInteger library or convert the inputs to integer directly.

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1. class Solution:
   
2.     def addStrings(self, num1: str, num2: str) -> str:
   
3.         i, j = len(num1) - 1, len(num2) - 1
   
4.         carry = 0
   
5.         total = 0
   
6.         result = ''
   
7.         while i >= 0 or j >= 0:
   
8.             total = carry
   
9.             if i >= 0:
   
10.                 total += ord(num1[i]) - 48
    
11.             if j >= 0:
    
12.                 total += ord(num2[j]) - 48
    
13.             result += str(total % 10)
    
14.             carry = total // 10
    
15.             i -= 1
    
16.             j -= 1
    
17.         if carry > 0:
    
18.             result += str(carry)
    
19.         return result[::-1]

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