package medium;

import datastructures.ListNode;

public class AddTwoNumbers {

public ListNode addTwoNumbers(ListNode l1, ListNode l2) {

int sum = 0;

int carry = 0;

ListNode head = new ListNode();

ListNode ptr = head;

while (l1 != null || l2 != null || carry > 0) {

if (l1 != null) {

sum += l1.val;

l1 = l1.next;

}

if (l2 != null) {

sum += l2.val;

l2 = l2.next;

}

sum += carry;

carry = sum / 10;

ptr.next = new ListNode(sum % 10);

sum = 0;

ptr = ptr.next;

}

return head.next;

}

}