题目

remove-linked-list

算法

* 迭代

* 递归

代码

* 迭代

class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        if (!head) return head;
        ListNode *dummy = new ListNode(-1);
        dummy->next = head;
        ListNode *cur = head;
        while (cur->next) {
            ListNode *tmp = cur->next;
            cur->next = tmp->next;
            tmp->next = dummy->next;
            dummy->next = tmp;
        }
        return dummy->next;
    }
};

* 递归

class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        if (!head || !head->next) return head;
        ListNode *p = head;
        head = reverseList(p->next);
        p->next->next = p;
        p->next = NULL;
        return head;
    }
};