You are given two non-empty linked lists representing two non-negative integers. 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.
You may assume the two numbers do not contain any leading zero, except the number 0 itself.
Your input {1,2,8} {1,8,1}
Your answer{2,0,0,1}
一道链表题 需要注意点的有三个
第一： 正常的进位问题（包括上一步运算的进位1 加上这次运算的结果又有进位）
第二： 如果两个链表不一样长，如何不在判断和向下传输的过程不返回空指针异常
第三： 最后一位运算时如果有进位怎么办；
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
class Solution {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode resultList = new ListNode(0);
ListNode temp = resultList;
ListNode mSum = new ListNode(0);
while(l1 != null || l2 != null){
int list1 = (l1 != null) ? l1.val : 0;
int list2 = (l2 != null) ? l2.val : 0;
int sum = list1 + list2;
int dSum = (sum + mSum.val) % 10;
//int input = (dSum + mSum.val) % 10;
temp = temp.next = new ListNode(dSum);
mSum = mSum.next = new ListNode((sum + mSum.val) / 10);
l1 = (l1 == null) ? null : l1.next;
l2 = (l2 == null) ? null : l2.next;
}
if(mSum.val == 1){
temp.next = new ListNode(1);
}
return resultList.next;
}
}
