2. 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.



主要注意连续进位的情况吧..其他没有什么难度

/**
 * 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) {
        bool carry=false;
        ListNode *res = NULL,*cur=NULL,*last=NULL;
        while(l1||l2||carry)
        {
            cur=new ListNode(0);
            if(last)last->next=cur;
            if(NULL==res)res=cur;
            int val=(l1?l1->val:0)+(l2?l2->val:0)+carry;
            carry=val>9?true:false;
            cur->val=val%10;
            if(l1)l1=l1->next;
            if(l2)l2=l2->next;
            last=cur;
        }
        return res;
    }
};