Add Two Numbers using Linked List

A linked list is a linear set of data items whose order is not determined by their physical location in memory in computer science. Instead, each element points to the next. It’s a data structure made up of a number of nodes that together form a sequence.

Add Two Numbers using Linked List:
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.

Solution for this program:

public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
    ListNode dummyHead = new ListNode(0);
    ListNode p = l1, q = l2, curr = dummyHead;
    int carry = 0;
    while (p != null || q != null) {
        int x = (p != null) ? p.val : 0;
        int y = (q != null) ? q.val : 0;
        int sum = carry + x + y;
        carry = sum / 10;
        curr.next = new ListNode(sum % 10);
        curr = curr.next;
        if (p != null) p = p.next;
        if (q != null) q = q.next;
    }
    if (carry > 0) {
        curr.next = new ListNode(carry);
    }
    return dummyHead.next;
}

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