题目： You are given two linked lists representing two non-negative numbers. 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.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
没啥好说的，类似与merge list的过程。对余下的list的操作可以合并，使代码看起来简洁。就是那个意思，体会一下。。。
1 public ListNode addTwoNumbers(ListNode l1, ListNode l2) { 2 ListNode A = l1; 3 ListNode B = l2; 4 int carry = 0; 5 ListNode newHead = new ListNode(0); 6 ListNode cur = newHead; 7 while(A != null || B != null){ 8 if (A != null){ 9 carry += A.val; 10 A = A.next; 11 } 12 if (B != null){ 13 carry += B.val; 14 B = B.next; 15 } 16 cur.next = new ListNode(carry % 10); 17 cur = cur.next; 18 carry /= 10; 19 } 20 if (carry == 1) { 21 cur.next = new ListNode(1); 22 } 23 return newHead.next; 24 }