LeetCode——Add Two Numbers

LeetCode——Add Two Numbers

leetcode上第二题：

题目内容：

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

题目翻译：

给定两个链表，它们代表两个非0的数，数字以逆序存在链表中，链表的每个结点包含一个单一的数。把这两个整数相加并以链表的形式返回。

解题思路：

主要考察链表的操作，两数的各位相加时注意进位。最后相加时注意最高位的值是否为1（即次高位想加时是否产生进位）感觉没有考察具体的算法。

<span style="font-size:14px;">/**
* Definition for singly-linked list.
* struct ListNode {
*     int val;
*     ListNode *next;
*     ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
ListNode rootNode(0);
ListNode *pCurNode = &rootNode;
int index = 0;
while(l1||l2)
{
int a = (l1?l1->val:0);
int b = (l2?l2->val:0);
int sum = a+b+index;
index = sum/10;
sum %= 10;
ListNode *newNode = new ListNode(sum);
pCurNode->next = newNode;
pCurNode = newNode;
if(l1)
l1 = l1->next;
if(l2)
l2 = l2->next;
}
if(index>0)
{
ListNode *newNode = new ListNode(index);
pCurNode->next = newNode;
}
return rootNode.next;
}
};</span>