1. public ListNode reverseList(ListNode head) {
    2.     ListNode curr = null;
    3.     ListNode pre = head;
    4.     while (pre != null) {
    5.         ListNode tempNode = pre.next;
    6.         pre.next = curr;
    7.         curr = pre;
    8.         pre = tempNode;
    9.     }
    10.     return curr;
    11. }

    倒序链表 - 图1