leetcode problem 206. Reverse Linked List

最新推荐文章于 2023-01-31 10:55:14 发布

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最新推荐文章于 2023-01-31 10:55:14 发布

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本文介绍了一种使用迭代方法实现链表反转的有效算法，并提供了详细的C++代码实现。该算法通过不断更新当前节点的指针方向来完成链表的反转过程。

Description

Reverse a singly linked list.

Example:

Input: 1->2->3->4->5->NULL
Output: 5->4->3->2->1->NULL
Follow up:

A linked list can be reversed either iteratively or recursively. Could you implement both?

Solution

mind that the head could be NULL

/**
 * 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) return head;
        ListNode* cur_head = NULL;
        ListNode* cur = head;
        ListNode* cur_next = cur->next;
        while(cur != NULL)
        {
            cur_next = cur->next;
            cur->next = cur_head;
            cur_head = cur;
            cur = cur_next;
        }
        return cur_head;
    }
};