Leetcode OJ Reverse Linked List

Topics

Ideas
Flip one-way linked list, here the topic requires recursive and non-recursive implementation, the specific ideas see code.

Code
a) non-recursive

struct ListNode* reverseList(struct ListNode* head) {    structNULL;    struct ListNode * OriPresent = head;    whileNULL) {        struct ListNode * Present = (struct ListNode*)malloc(sizeof(struct ListNode));        Present->val = OriPresent->val;        Present->next = Before;        Before = Present;        OriPresent = OriPresent->next;    }    return Before;}

b) recursion

struct  listnode * Reverse (struct  ListNode * before, struct  ListNode * oripresent) {if  (oripresent = = null )  return  before; struct  ListNode * Present = (struct  listnode*) malloc (sizeof  (struct  listnode)); Present->next = before; Present->val = oripresent->val; return  reverse (Present, oripresent->next);} struct  listnode* reverselist (struct  listnode* head) {return< /span> Reverse (null , head);} 

Leetcode OJ Reverse Linked List