【LeetCode】206.反转链表

leetcode链接 206. 反转链表

#include <stdio.h> struct ListNode { int val; struct ListNode* next; }; typedef struct ListNode ListNode; struct ListNode* reverseList1(struct ListNode* head) { if (head != NULL) { ListNode* n1 = NULL; ListNode* n2 = head; ListNode* n3 = n2->next; while (n2 != NULL) { n2->next = n1; n1 = n2; n2 = n3; if (n3 != NULL) { n3 = n3->next; } } return n1; } return NULL; } ListNode* reverseList2(ListNode* head) { if (head) { ListNode* newhead = NULL; ListNode* cur = head; while (cur) { ListNode* next = cur->next; cur->next = newhead; newhead = cur; cur = next; } return newhead; } return NULL; }