leetcode-day8:Reverse Linked List(反转链表)

链表：听说过两天反转链表又写不出来了？

Given the head of a singly linked list, reverse the list, and return the reversed list.
Example 1:

Input: head = [1,2,3,4,5]
Output: [5,4,3,2,1]

Example 2:

Input: head = [1,2]
Output: [2,1]

Example 3:

Input: head = []
Output: []

Constraints:

The number of nodes in the list is the range [0, 5000].
-5000 <= Node.val <= 5000

JAVA代码实现：

class Solution {
    public ListNode reverseList(ListNode head) {
		ListNode cur = head;
		ListNode pre = null;
		ListNode temp = null;
		//1->2->3->null
		//null 1->2->3->null
		while(cur!=null){
			temp=cur.next;
			cur.next=pre;
			pre=cur;
            cur=temp;
			
		}
        return pre;
    }
}