Title description

Give you the head node of the singly linked list head, please reverse the linked list and return the reversed linked list.

Solution ideas

• This is a simple question about linked lists, examining the inversion of linked lists;

• We consider changing the point of the pointer, no need to create a new linked list;

• Leverage a picture from Karge:

  

Input and output example

Code

/*** Definition for singly-linked list.* public class ListNode {* int val;*ListNode next;* ListNode() {}* ListNode(int val) { this.val = val; }* ListNode(int val, ListNode next) { this.val = val; this.next = next; }* }*/class Solution {public ListNode reverseList(ListNode head) {ListNode pre = null;ListNode tem = null;ListNode cur = head;while(cur != null){tem = cur.next;cur.next = pre;pre = cur;cur = item;}return pre;}}