02.输入一个链表，从尾到头打印链表每个节点的值

/**
*    public class ListNode {
*        int val;
*        ListNode next = null;
*
*        ListNode(int val) {
*            this.val = val;
*        }
*    }
*
*/
import java.util.ArrayList;
public class Solution {
    public ArrayList<Integer> printListFromTailToHead(ListNode listNode) {
        ArrayList<Integer> list = new ArrayList<Integer>();
        if(listNode == null) return list;
　　　　　//倒序输出，可以先将链表反序，再添加
        ListNode pre , now ,temp;
        pre = listNode;
        now = pre.next;
        pre.next = null;
        while(now != null){
            temp = now.next;
            now.next = pre;
            pre = now;
            now = temp;
        }
        while(pre != null){
            list.add(pre.val);
            pre = pre.next;
        }
        return list;
        
    }
}