2 两数相加

  1. /**
  2.  * Definition for singly-linked list.
  3.  * public class ListNode {
  4.  *     int val;
  5.  *     ListNode next;
  6.  *     ListNode(int x) { val = x; }
  7.  * }
  8.  */
  9. class Solution {
  10.     public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
  11.         ListNode head = new ListNode(0);
  12.         ListNode p = l1, q = l2, cur = head;
  13.         int flag = 0;
  14.         while (p != null || q != null) {
  15.             int x = (p != null) ? p.val : 0;
  16.             int y = (q != null) ? q.val : 0;
  17.             int sum = x + y + flag;
  18.             flag = sum / 10;
  19.             cur.next = new ListNode(sum % 10);
  20.             cur = cur.next;
  21.             if (p != null) p = p.next;
  22.             if (q != null) q = q.next;
  23.         }
  24.         if (flag > 0) 
  25.             cur.next = new ListNode(flag);
  26.         return head.next;
  27.     }
  28. }