Given two non-negative integers num1
and num2
represented as string, return the sum of num1
and num2
.
Note:
- The length of both
num1
andnum2
is < 5100. - Both
num1
andnum2
contains only digits0-9
. - Both
num1
andnum2
does not contain any leading zero. - You must not use any built-in BigInteger library or convert the inputs to integer directly.
class Solution {
public:
string addStrings(string num1, string num2) {
string ans="";
int i=num1.size()-1,j=num2.size()-1;
int sum=0;
while(i>=0||j>=0)
{
int a=i>=0?num1[i--]-'0':0;
int b=j>=0?num2[j--]-'0':0;
sum+=a+b;
ans.insert(ans.begin(),'0'+sum%10);
sum/=10;
}
if(sum>0)
ans.insert(ans.begin(),'0'+sum);
return ans;
}
};