Description:

Given the string representations of two integers, return the string representation of the sum of those integers.

For example:

sumStrings('1','2') // => '3'

A string representation of an integer will contain no characters besides the ten numerals "0" to "9".

I have removed the use of BigInteger and BigDecimal in java.

Python: your solution need to work with huge numbers (about a milion digits), converting to int will not work.

My solution

using System.Numerics;

public static class Kata
{
    public static string sumStrings(string a, string b)
    {
        if (a == "") 
            a = "0";

        return (BigInteger.Parse(a) + BigInteger.Parse(b)).ToString();
    }
}