Leetcode - 两数相加

解题思路：(Cpp)
直接上代码。

/**
 * 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* dummyHead = new ListNode(0);
        ListNode* curr = dummyHead;
        int carry = 0;
        int sum;
        while (l1 || l2){
            sum = 0;
            if (l1){
                sum += l1->val;
                l1 = l1->next;
            }
            if (l2){
                sum += l2->val;
                l2 = l2->next;
            }
            sum += carry;
            carry = sum / 10;
            curr->next = new ListNode(sum % 10);
            curr = curr->next;
        }
        if (carry > 0) 
            curr->next = new ListNode(carry);
        return dummyHead->next;
    }
};