Given two non-negative integers, num1 and num2, represented as strings, return the sum of num1 and num2 as a string.
You must not use any built-in library for handling large integers (such as BigInteger) or directly convert the inputs to integers.
Constraints:
num1.length, num2.length
num1 and num2 consist of only digits.
num1 and num2 don’t have any leading zeros except for the zero itself.
Given two non-negative integers, num1 and num2, represented as strings, return the sum of num1 and num2 as a string.
You must not use any built-in library for handling large integers (such as BigInteger) or directly convert the inputs to integers.
Constraints:
num1.length, num2.length
num1 and num2 consist of only digits.
num1 and num2 don’t have any leading zeros except for the zero itself.