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>