2. Add Two Numbers
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
处理好进位
1 /** 2 * Definition for singly-linked list. 3 * struct ListNode { 4 * int val; 5 * ListNode *next; 6 * ListNode(int x) : val(x), next(NULL) {} 7 * }; 8 */ 9 class Solution { 10 public: 11 ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) { 12 ListNode* newHead = new ListNode(0); 13 ListNode* pNode = newHead; 14 15 int num = 0; 16 17 while(l1 != NULL || l2 != NULL){ 18 int val = num + (l1 ? l1->val : 0) + (l2 ? l2->val: 0); 19 num = val /10; 20 val = val % 10; 21 pNode->next = new ListNode(val); 22 pNode = pNode->next; 23 if(l1 != NULL){ 24 l1 = l1->next; 25 } 26 if(l2 != NULL){ 27 l2 = l2->next; 28 } 29 } 30 if(num != 0){ 31 pNode->next = new ListNode(num); 32 pNode = pNode->next; 33 } 34 return newHead->next; 35 } 36 };