LeetCode - Add Two Numbers

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Example:

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

Java Solution:

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode temp = new ListNode(0);
        int carry = 0;
        ListNode headA =l1 , headB = l2 , curr = temp;
     
           while (headA != null || headB !=null){
                int x = (headA != null) ? headA.val : 0;
                int y = (headB != null) ? headB.val : 0;
                int sum = x + y + carry;
                carry = sum / 10;
                curr.next = new ListNode(sum % 10);     
                curr = curr.next;
               if(headA != null) headA = headA.next;
               if(headB != null) headB = headB.next;
           }
            if(carry > 0)
                curr.next = new ListNode(carry);
            return temp.next;
        
    }
}

Time Complexity : O(max(m,n))

Space Complexity : O(max(m,n))+1