LeetCode 第二題答案 C++
/**
* 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 *head = NULL, *p;
int carry = 0, sum;
while (l1 != NULL || l2 != NULL || carry != 0) {
sum = 0;
if (l1 != NULL) {
sum += l1->val;
l1 = l1->next;
}
if (l2 != NULL) {
sum += l2->val;
l2 = l2->next;
}
sum += carry;
carry = sum / 10;
sum %= 10;
ListNode *newNode = new ListNode(sum);
if (head == NULL) {
head = newNode;
p = newNode;
} else{
p->next = newNode;
p = p->next;
}
}
return head;
}
};