Java算法之两数之加

2

class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
       ListNode pre = new ListNode(0);
       ListNode cur = pre;
       int carry = 0;
       while(l1!=null||l2!=null){
           int x = l1==null?0:l1.val;
           int y = l2==null?0:l2.val;
           int sum = x+y+carry;
           carry = sum/10;
           sum = sum%10;
           cur.next = new ListNode(sum);
           cur = cur.next;
           if(l1!=null){
               l1 = l1.next;
           }
           if(l2!=null){
               l2 = l2.next;
           }
       }
       if(carry == 1) {
            cur.next = new ListNode(carry);
        }
       return pre.next;
    }
}