[LeetCode] 2. Add Two Numbers

 

 

 

https://leetcode.com/problems/add-two-numbers/description/

 

public class Solution {
    public ListNode AddTwoNumbers(ListNode l1, ListNode l2)
    {
        var head = new ListNode();
        var current = head;

        bool carry = false;

        while (((l1 != null) || (l2 != null)) || carry)
        {
            int sum = 0;

            if (carry)
            {
                ++sum;
                carry = false;
            }

            if (l1 != null)
            {
                sum += l1.val;
                l1 = l1.next;
            }

            if (l2 != null)
            {
                sum += l2.val;
                l2 = l2.next;
            }

            if (sum >= 10)
            {
                sum %= 10;
                carry = true;
            }

            current.next = new ListNode(sum);
            current = current.next;
        }

        return head.next;
    }
}