leetcode刷题36

class Solution {
    public ListNode reverseList(ListNode head) {
        return this.recursion(head,null);
    }
    public ListNode recursion(ListNode head,ListNode pre){
        if (head==null){
            return pre;
        }
        ListNode node=head.next;
        head.next=pre;
        return this.recursion(node,head);
    }
}