解题思路缺位的节点进行补零处理如97323补充为973023注意相加的进位问题class Solution { public ListNode addTwoNumbers(ListNode l1, ListNode l2) { ListNode head null, cur null; int carry 0; while (l1 ! null || l2 ! null) { int n1 l1 ! null ? l1.val : 0; int n2 l2 ! null ? l2.val : 0; int sum n1 n2 carry; if (head null) { head cur new ListNode(sum % 10); } else { cur.next new ListNode(sum % 10); cur cur.next; } carry sum / 10; if (l1 ! null) l1 l1.next; if (l2 ! null) l2 l2.next; } if (carry 0) cur.next new ListNode(carry); return head; } }