leecode-两数相加

/**
 * 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* p1 = l1;
        ListNode* p2 = l2;
        int num1, num2, num;
        num = p1->val + p2->val;
        int ge_wei = num % 10;
        int shi_wei = num / 10;
        struct ListNode* l3 = new ListNode(ge_wei);
        p1 = p1->next;
        p2 = p2->next;
        ListNode* p3 = l3;
        while(p1 || p2){
            if(p1)
                num1 = p1->val;
            else
                num1 = 0;
            if(p2)
                num2 = p2->val;
            else
                num2 = 0;
            num = num1 + num2 + shi_wei;
            ge_wei = num % 10;
            struct ListNode* new_p = new ListNode(ge_wei);
            p3->next = new_p;
            p3 = new_p;
            shi_wei = num / 10;
            if(p1)
                p1 = p1->next;
            if(p2)
                p2 = p2->next;
        }
        if(!p1 && !p2 && num > 9){
            struct ListNode* new_p = new ListNode(shi_wei);
            p3->next = new_p;
            p3 = new_p;
        }
        return l3;
    }
};