从尾到头打印链表

没什么难度，AC代码如下：

/**
*    public class ListNode {
*        int val;
*        ListNode next = null;
*
*        ListNode(int val) {
*            this.val = val;
*        }
*    }
*
*/
import java.util.ArrayList;
import java.util.Collections;
public class Solution {
    public ArrayList<Integer> printListFromTailToHead(ListNode listNode) {
       ArrayList<Integer> result=new ArrayList<>();
        while(listNode!=null){
            result.add(listNode.val);
            listNode=listNode.next;
        }
       Collections.reverse(result);
        return result;
    }
}

利用栈

/**
*    public class ListNode {
*        int val;
*        ListNode next = null;
*
*        ListNode(int val) {
*            this.val = val;
*        }
*    }
*
*/
import java.util.ArrayList;
import java.util.Stack;
public class Solution {
    public ArrayList<Integer> printListFromTailToHead(ListNode listNode) {
       ArrayList<Integer> result=new ArrayList<>();
        Stack<Integer> stack=new Stack<Integer>();
        if(listNode==null)
            return result;
        while(listNode!=null){
            stack.push(listNode.val);
            listNode=listNode.next;
        }
        while(!stack.isEmpty()){
            result.add(stack.pop());
        }
        return result;
    }
}