题解 | #大数加法#

class Solution:
    def solve(self , s , t ):
        # write code here
        # mimic the plus calculation. not allowed using inte converter 
        #add=0
        #fill zero in shorter string to make same length and then we can 
        # perform add index by index 
        # time complexity O(n) n is the max length 
        max_len= len(s) if len(s)>len(t) else len(t)
        s=s.zfill(max_len)
        t=t.zfill(max_len)
        add = 0
        res=''
        for i in range(max_len-1,-1,-1):
            temp=int(s[i])+int(t[i])+add
            res=res+str(temp%10)  #0
            add=temp//10
        if add>0:
            res=res+str(add)
        new_res=''
        for i in range(len(res)-1,-1,-1):
            new_res+=res[i]
            
        return new_res