LeetCode-206. Reverse Linked List（反转链表）

反转链表

Reverse Linked List

解

方法一：迭代

/**
https://leetcode-cn.com/problems/reverse-linked-list/ * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        ListNode* cur = NULL;
        while (head) {
            ListNode* temp = cur;
            cur = head;
            head = head->next;
            cur->next = temp;
        }

        return cur;
    }
};

方法二：递归

/**
https://leetcode-cn.com/problems/reverse-linked-list/ * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        if (head == NULL || head->next == NULL) {
            return head;
        }
        ListNode* cur = reverseList(head->next);
        head->next->next = head;
        head->next = NULL;
        return cur;
    }
};

来源：CSDN

作者：三九_感冒灵

链接：https://blog.csdn.net/weixin_43443553/article/details/104617057