leetcode2leetcode2

/**
 * 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) {
        int t = 0;
        ListNode left = l1;
        ListNode right = l2;
        boolean flat = true;
        ListNode result = null;
         ListNode header = null;
        while(flat){
            flat = false;
            if (left!=null){
                t = t+left.val;
                left = left.next;
                flat = true;
            }
            if (right!=null){
                t = t+right.val;
                right = right.next;
                flat = true;
            }
            
          
            if (flat || t!=0){
                 int x = t % 10;
                 t = t/10;
                 if (result==null){
                    result = new ListNode(x);  
                    header = result;
                 }else{
                    ListNode next = new ListNode(x); 
                    result.next = next;
                    result = next;
                 }
            }
        }
        return header;
    }
}