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.

``````/*
*/

public static void main(String[] args) {
ListNode l1 = new ListNode(2);
l1.next = new ListNode(4);
l1.next.next = new ListNode(3);

ListNode l2 = new ListNode(5);
l2.next = new ListNode(6);
l2.next.next = new ListNode(4);

}

private void print(ListNode node) {
for (; node != null; node = node.next) {
System.out.print(node.val);
System.out.print("->");
}
System.out.println("null");
}

private ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode node = new ListNode(0);
int carry = 0;
while (l1 != null || l2 != null) {
int val = 0;
if (l1 != null) {
val += l1.val;
l1 = l1.next;
}
if (l2 != null) {
val += l2.val;
l2 = l2.next;
}
val += carry;
node.next = new ListNode(val % 10);
carry = val / 10;
node = node.next;
}
if (carry > 0)
node.next = new ListNode(carry);