https://leetcode.com/problems/add-two-numbers/
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.
Example:
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4) Output: 7 -> 0 -> 8 Explanation: 342 + 465 = 807.
代码：
/**
* 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 *res = new ListNode(-1);
ListNode *cur = res;
int k = 0;
while(l1 || l2) {
int n1 = l1 ? l1 -> val : 0;
int n2 = l2 ? l2 -> val : 0;
int sum = n1 + n2 + k;
k = sum / 10;
cur -> next = new ListNode(sum % 10);
cur = cur -> next;
if(l1) l1 = l1 -> next;
if(l2) l2 = l2 -> next;
}
if(k) cur -> next = new ListNode(1);
return res -> next;
}
};