import java.util.Stack;

/**

* created by zl on 2019/5/15 20:27

*/

public class medium_445_AddTwoNumbersII {

public ListNode addTwoNumbers(ListNode l1, ListNode l2)

{

Stack<Integer> s1 = new Stack<Integer>();

Stack<Integer> s2 = new Stack<Integer>();

while(l1 != null)

{

s1.push(l1.val);

l1 = l1.next;

}

while(l2 != null)

{

s2.push(l2.val);

l2 = l2.next;

}

int sum = 0;

ListNode list = new ListNode(0);

while (!s1.empty() || !s2.empty())

{

if (!s1.empty())

sum += s1.pop();

if (!s2.empty())

sum += s2.pop();

list.val = sum % 10;

ListNode head = new ListNode(sum/10);

head.next = list;

list = head;

sum /= 10;

}

return list.val == 0 ? list.next : list;

}

}