LeetCode 206. Reverse Linked List

描述

解决

/**
* 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)
return NULL;
ListNode* tHead = head;
while (head -> next)
{
ListNode* tmp = head -> next;
head -> next = tmp ? tmp -> next : NULL;
if (tmp)
{
tmp -> next = tHead;
tHead = tmp;
}

}
return tHead;
}
};

/**
* 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) {
ListNode* tHead = NULL;
while (head)
{
ListNode *tmp = head;
head = head -> next;
tmp -> next = tHead;
tHead = tmp;
}
return tHead;
}
};