剑指Offer03

package javaOffer;

import java.util.ArrayList;
import java.util.List;
import java.util.Stack;


public class o03_ListFromTailtoHead_03 {


    public class ListNode{
        public int val;
        public ListNode next=null;

        public ListNode(int val) {
            this.val = val;
        }
    }

    //递归方式
    ArrayList arrayList=new ArrayList();
    public ArrayList<Integer> printListFromTailToHead(ListNode listNode) {
        if(listNode!=null){
            printListFromTailToHead(listNode.next);
            arrayList.add(listNode.val);
        }

        return arrayList;
    }

    //非递归模式
        public ArrayList<Integer> printListFromTailToHeadStack(ListNode listNode){
        Stack<Integer> stack=new Stack<>();
        while(listNode!=null){
            stack.push(listNode.val);
            listNode=listNode.next;
        }

        ArrayList arrayList=new ArrayList();
        while(stack!=null){
            arrayList.add(stack.pop());
        }
        return arrayList;
    }
}