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leetode 2 add two numbers

admin 11月 13, 2020 0

Description

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.

Example:

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

解题思路

题目要求两个链表从头开始相加。

AC代码


 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class  {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
        ListNode* preHead = new ListNode(0);
        ListNode* p = preHead;
        int extra=0;
        int sum;
        while(l1||l2||extra){
            sum += extra;
            sum+=l1?l1->val:0;
            sum+=l2?l2->val:0;
            l1=l1?l1->next:l1;
            l2=l2?l2->next:l2;
            extra =sum/10;
            p->next = new ListNode(sum%10);
            p = p->next;
            sum=0;
        }
        return preHead->next;
    }
};

题目链接

Add Two Numbers