java实现翻转链表

给出一个链表1->2->3->null，这个翻转后的链表为3->2->1->null

public ListNode reverse(ListNode head) { if(head == null){ return null; } //用来保存上一个tmp ListNode prev = null; while (head != null) { ListNode tmp = head; head = head.next; tmp.next = prev; prev = tmp; } return prev； }

缺陷：没有在原链表的基础上进行反转

public ListNode ReverseList(ListNode head) { if(head == null){ return null; } ListNode rHead = null; ListNode prior = null;//store prior ListNode q = head;//store current while(q != null){ ListNode next = q.next;//store the next if(next == null){ rHead = q; } q.next = prior; prior = q; q = next; } return rHead; }