/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
#define MNEXT(A) (A?(A->next?A->next:NULL):NULL)
#define MSELECT(A,B) (A?A:(B?B:NULL))
class Solution {
public:
ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
if (!l1 && !l2) return NULL;
ListNode *n=new ListNode(0);
if (l1) n->val+=l1->val;
if (l2) n->val+=l2->val;
if (n->val>9)
{
ListNode *next;
next=MNEXT(l1);
if (!next) next=MNEXT(l2);
if (next) // next node(s) exists, so hand over 1 to next digit
{
next->val += 1;
}
else // no next node found, so create new node with initial value=1
{
ListNode *p=MSELECT(l1,l2);
p->next=new ListNode(1);
}
n->val -=10;
}
if (MNEXT(l1) || MNEXT(l2))
n->next = addTwoNumbers(MNEXT(l1), MNEXT(l2));
return n;
}
};
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