LeetCode-C#-0002.两数相加

题目描述：
给定两个非空链表，表示两个非负整数。数字以相反的顺序存储，每个节点包含一个数字。将这两个数字相加并以链表的形式返回。

示例：
输入：(2 ->4 ->3) + (5 ->6 ->4)
输出：7 ->0 ->8解释：342 +465 =807代码示例：

csharppublic class ListNode {
 public int val;
 public ListNode next;
 public ListNode(int val=0, ListNode next=null) {
 this.val = val;
 this.next = next;
 }
}

public class Solution {
 public ListNode AddTwoNumbers(ListNode l1, ListNode l2) {
 ListNode dummyHead = new ListNode(0);
 ListNode p = l1, q = l2, curr = dummyHead;
 int carry =0;
 while (p != null || q != null) {
 int x = (p != null) ? p.val :0;
 int y = (q != null) ? q.val :0;
 int sum = carry + x + y;
 carry = sum /10;
 curr.next = new ListNode(sum %10);
 curr = curr.next;
 if (p != null) p = p.next;
 if (q != null) q = q.next;
 }
 if (carry >0) {
 curr.next = new ListNode(carry);
 }
 return dummyHead.next;
 }
}