题解 | #二叉树的下一个结点#

import java.util.*;
/*
public class TreeLinkNode {
    int val;
    TreeLinkNode left = null;
    TreeLinkNode right = null;
    TreeLinkNode next = null;

    TreeLinkNode(int val) {
        this.val = val;
    }
}
*/
public class Solution {
    public TreeLinkNode GetNext(TreeLinkNode pNode) {
        if (pNode.next == null && pNode.left == null && pNode.right == null)return null;
        TreeLinkNode node = pNode;
        List<TreeLinkNode> list = new ArrayList<>();
        while (node.next != null) {
            node = node.next;
        }
        vinOrder(node, list);
        for (int i = 0; i  < list.size() - 1; i++) {
            if (list.get(i).val == pNode.val) {
                return list.get(i + 1);
            }
        }
        return null;
    }
    public void vinOrder(TreeLinkNode node, List<TreeLinkNode> list) {
        if (node == null) {
            return;
        }
        vinOrder(node.left, list);
        list.add(node);
        vinOrder(node.right, list);
        return;
    }

}