二叉树的下一节点

/*
public class TreeLinkNode {
    int val;
    TreeLinkNode left = null;
    TreeLinkNode right = null;
    TreeLinkNode next = null;

    TreeLinkNode(int val) {
        this.val = val;
    }
}
*/
public TreeLinkNode GetNext(TreeLinkNode pNode)
    {
           if(pNode==null) return null;
        TreeLinkNode pNext=null;
        if(pNode.right!=null){
            TreeLinkNode pRight=pNode.right;
            while(pRight.left!=null)
                pRight=pRight.left;
            
            pNext=pRight;
        }else if(pNode.next!=null){
            TreeLinkNode cur=pNode;
            TreeLinkNode parent=pNode.next;
            while(parent!=null&&cur==parent.right){
                cur=parent;
                parent=parent.next;
            }
            pNext=parent;
        }
        return pNext;
    }