一.题目及剖析

https://leetcode.cn/problems/reverse-linked-list/description/

二.思路引入

设定三个指针,n1指向空, n2指向head,n3指向下一个元素,将n2->next指向n1,然后三个指针向后遍历重复即可

三.代码引入

/*** Definition for singly-linked list.* struct ListNode {*     int val;*     struct ListNode *next;* };*/
struct ListNode* reverseList(struct ListNode* head) {struct ListNode *n1, *n2, *n3;n1 = NULL;n2 = n3 = head;if(head)n3 = head->next;while(n2){n2->next = n1;n1 = n2;n2 = n3;if(n3)n3 = n3->next;}return n1;
}