LeetCode 2 两数相加

LeetCode 2 两数相加

https://leetcode-cn.com/problems/add-two-numbers/

一道相对简单的题目，模拟两个数的加法即可。

class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
        int sum = 0, carry = 0;
        ListNode dummy(0);
        ListNode *tail = &dummy;
        while (l1 != nullptr && l2 != nullptr) {
            sum = l1->val + l2->val + carry;
            carry = sum / 10;
            sum = sum % 10;
            
            tail->next = new ListNode(sum);
            tail = tail->next;
            l1 = l1->next;
            l2 = l2->next;
        }

        ListNode *left = l1 == nullptr ? l2 : l1;
        while (left != nullptr) {
            sum = left->val + carry;
            carry = sum / 10;
            sum = sum % 10;

            tail->next = new ListNode(sum);
            tail = tail->next;
            left = left->next;
        }

        if (carry > 0) tail->next = new ListNode(carry);
        return dummy.next;
    }
};