LeetCode 206: Reverse Linked List

LeetCode Linked List

Reverse a singly linked list.Hint: A linked list can be reversed either iteratively or recursively. Could you implement both?

题意

翻转该单链表

思路

使用迭代法或者递归法皆可实现。

代码

C语言版本：
iteratively(迭代方法)

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
struct ListNode* reverseList(struct ListNode* head) {
    if (NULL == head){
        return head;
    }
    struct ListNode *p = head;
    p = head->next;
    head->next = NULL;
    while (p != NULL){
        struct ListNode *pNext = p->next;
        p->next = head;
        head = p;
        p = pNext;
    }
    return head;
}