天天看点

LeetCode206(反转链表)

菜鸟成长逆袭之旅,爱好撸铁和撸代码,有强制的约束力,希望通过自己的努力做一个高品质人

Work together and make progress together

反转链表

反转一个单链表。

示例:

输入: 1->2->3->4->5->NULL

输出: 5->4->3->2->1->NULL

进阶:

你可以迭代或递归地反转链表。你能否用两种方法解决这道题?

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


 * 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 *newHead = NULL;
		while(head){
			ListNode *t = head->next;
			head->next = newHead;
			newHead = head;
			head = t;
		}
        return newHead;
    }
};