Day3 剑指offer：逆序链表

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;
import java.util.ArrayDeque;
public class Solution {
   public ArrayList<Integer> printListFromTailToHead2(ListNode listNode) {
    ArrayList<Integer> res = new ArrayList<>();
    Deque<Integer> stack = new ArrayDeque<>();
    while (listNode != null) {
        stack.push(listNode.val);
        listNode = listNode.next;
    }
    while (!stack.isEmpty()) {
        res.add(stack.pop());
    }
    return res;
}
}