合并零之间的节点

#leetcode #链表 
class Solution {
public:
    ListNode* mergeNodes(ListNode* head) {
        auto tail = head;
        for (auto cur = head->next; cur->next; cur = cur->next) {
            if (cur->val) {
                tail->val += cur->val;
            } else {
                tail = tail->next;
                tail->val = 0;
            }
        }
        // 注：这里没有 delete 剩余节点，可以自行补充
        tail->next = nullptr;
        return head;
    }
};