LeetCode 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.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)

Output: 7 -> 0 -> 8

answer:

class Solution {
public:
ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
ListNode * resultP = new ListNode(0) ;
ListNode * head = resultP;
ListNode * pre ;

while((l1 != NULL) && (l2 != NULL)){
int jinwei = resultP->val;
int sum = l1->val + l2->val + jinwei;
jinwei = sum / 10;
sum = sum % 10;
pre = resultP;
resultP->val = sum;
resultP->next = new ListNode(jinwei);
resultP = resultP->next;
l1 = l1->next;
l2 = l2->next;
}
ListNode * temp =NULL;
if(l1 != NULL) temp = l1;
if(l2 != NULL) temp = l2;
while(temp != NULL){
int jinwei = resultP->val;
int sum = temp->val + jinwei;
jinwei = sum / 10;
sum = sum % 10;
pre = resultP;
resultP->val = sum;
resultP->next = new ListNode(jinwei);
resultP = resultP->next;
temp = temp->next;
}
if(resultP->val == 0)
pre->next = NULL;
return head;
}
};