剑指 Offer 06. 从尾到头打印链表 #

题目 #

输入一个链表的头节点，从尾到头反过来返回每个节点的值（用数组返回）。

思路 #

代码 #

public class ListNode {
    int val;
    ListNode next;
    ListNode(int x) { val = x; }
}
class Solution {
    public void helper(ListNode head, List<Integer> resultList) {
        if (head == null) return;
        else if (head.next == null) resultList.add(head.val);
        else {
            helper(head.next, resultList);
            resultList.add(head.val);
        }
    }
    public int[] reversePrint(ListNode head) {
        List<Integer> resultList = new ArrayList<>();
        helper(head, resultList);
        int[] result = new int[resultList.size()];
        for (int i=0; i<resultList.size(); i++) result[i] = resultList.get(i);
        return result;
    }
}