You are given two linked lists representing two non-negative numbers. 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.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
代码：
1 ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) { 2 // IMPORTANT: Please reset any member data you declared, as 3 // the same Solution instance will be reused for each test case. 4 if(l1 == NULL) 5 return l2; 6 if(l2 == NULL) 7 return l1; 8 ListNode *result, *tmp; 9 int carry = 0; 10 tmp = new ListNode(0); 11 result = tmp; 12 while(l1 && l2){ 13 tmp->next = new ListNode(0); 14 tmp->next->val = l1->val + l2->val + carry; 15 carry = tmp->next->val/10; 16 tmp->next->val = tmp->next->val%10; 17 tmp = tmp->next; 18 l1 = l1->next; 19 l2 = l2->next; 20 } 21 if(l1 == NULL) 22 tmp->next = l2; 23 else 24 tmp->next = l1; 25 while(carry == 1){ 26 if(tmp->next == NULL) 27 tmp->next = new ListNode(0); 28 tmp->next->val++; 29 carry = tmp->next->val/10; 30 tmp->next->val = tmp->next->val%10; 31 tmp = tmp->next; 32 } 33 return result->next; 34 }