2021-10-14 06. 从尾到头打印链表（递归法、辅助栈法）

解题思路

方法一：辅助栈：

代码

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
     
    public int[] reversePrint(ListNode head) {
     
        LinkedList<Integer> stack = new LinkedList<Integer>();
        while(head != null) {
     
            stack.addLast(head.val);
            head = head.next;
        }
        int[] res = new int[stack.size()];
        for(int i = 0; i < res.length; i++)
            res[i] = stack.removeLast();
    return res;
    }
}

方法二：递归法

class Solution {
     
    ArrayList<Integer> tmp = new ArrayList<Integer>();
    public int[] reversePrint(ListNode head) {
     
        recur(head);
        int[] res = new int[tmp.size()];
        for(int i = 0; i < res.length; i++)
            res[i] = tmp.get(i);
        return res;
    }
    void recur(ListNode head) {
     
        if(head == null) return;
        recur(head.next);
        tmp.add(head.val);
    }
}