leetCode算法题目之我解（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

需要注意的是进位和指针操作！

/**
 * 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 *result = l1;
    ListNode *p1 = l1;
    ListNode *p2 = l2;
    ListNode *pre = l1;
    int s = 0;
    while (p1 && p2) {
        pre = p1;
        int temp = s;
        s = (p1->val + p2->val + s) / 10;
        p1->val = (p1->val + p2->val + temp) % 10;
        p1 = p1->next;
        p2 = p2->next;
    }
    if (p2) {
        pre->next = p2;
        p1 = p2;
    }
    while (p1) {
        pre = p1;
        if (s != 0) {
            int temp = s;
            s = (p1->val + s) / 10;
            p1->val = (p1->val + temp) % 10;
            p1 = p1->next;
        } else {
            break;
        }
    }
    if (s) {
        pre->next = new ListNode(s);
    }
    return result;
    }
};