Add Strings

def addStrings(num1, num2):
    result = []
    carry = 0
    i, j = len(num1) - 1, len(num2) - 1

    while i >= 0 or j >= 0 or carry:
        n1 = int(num1[i]) if i >= 0 else 0
        n2 = int(num2[j]) if j >= 0 else 0

        total = n1 + n2 + carry
        result.append(str(total % 10))
        carry = total // 10

        i -= 1
        j -= 1

    return ''.join(reversed(result))

class Solution {
public:
    string addStrings(string num1, string num2) {
        string result = "";
        int carry = 0;
        int i = num1.length() - 1;
        int j = num2.length() - 1;

        while (i >= 0 || j >= 0 || carry) {
            int n1 = i >= 0 ? num1[i] - '0' : 0;
            int n2 = j >= 0 ? num2[j] - '0' : 0;

            int total = n1 + n2 + carry;
            result = char((total % 10) + '0') + result;
            carry = total / 10;

            i--;
            j--;
        }

        return result;
    }
};

function addStrings(num1: string, num2: string): string {
    let result = "";
    let carry = 0;
    let i = num1.length - 1;
    let j = num2.length - 1;

    while (i >= 0 || j >= 0 || carry) {
        const n1 = i >= 0 ? parseInt(num1[i]) : 0;
        const n2 = j >= 0 ? parseInt(num2[j]) : 0;

        const total = n1 + n2 + carry;
        result = String(total % 10) + result;
        carry = Math.floor(total / 10);

        i--;
        j--;
    }

    return result;
}