方法一

思路：直接反转即可

  1. /**
  2.  * Definition for singly-linked list.
  3.  * type ListNode struct {
  4.  *     Val int
  5.  *     Next *ListNode
  6.  * }
  7.  */
  8. func reverseList(head *ListNode) *ListNode {
  10.     var prev *ListNode
  12.     cur := head
  14.     for cur != nil {
  15.         prev, cur.Next, cur = cur, prev, cur.Next
  16.     }
  18.     return prev
  19. }