链表相加

链接

class Solution
{
public:
    ListNode *addTwoNumbers(ListNode *l1, ListNode *l2)
    {
        ListNode *pre = new ListNode(0);
        ListNode *cur = pre;
        int carry = 0;
        while (l1 || l2)
        {
            int n1 = l1 ? l1->val : 0;
            int n2 = l2 ? l2->val : 0;
            int sum = n1 + n2 + carry;
            cur->next = new ListNode(sum % 10);
            cur=cur->next;
            carry = sum / 10;
            if (l1)
            {
                l1 = l1->next;
            }
            if (l2)
            {
                l2 = l2->next;
            }
        }
        if (carry > 0)
        {
            cur->next = new ListNode(carry);
        }
        return pre->next;
    }

};