@Override
	public Node findKey(int value) {
		return this.findKey(value, root);
		
	
	} 

	public Node findKey(int value,Node root) {
		if(root == null){
			return null;
		}else if(root != null && root.value == value){
			return root;
		}else {
			Node node1 = this.findKey(value, root.leftChild);
			Node node2 = this.findKey(value, root.rightChild);
			if(node1 != null && node1.value == value){
				return node1;
			}else if(node2 != null && node2.value == value){
				return node2;
			}else{
				return null;
			}
		}
		
	} 
	
	
	public Node findKey2(int value) {
		Node node = null;
		// 中序遍历左子树
		if (root.leftChild != null) {
			BinaryTree leftTree = new LinkedBinaryTree(root.leftChild);
			node = leftTree.findKey(value);
		}
		if (node != null) {
			return node;
		} else {
			// 判断根是否等于要查询值
			if (root.value == value) {
				return root;
			} else {
				// 中序遍历右子树
				if (root.rightChild != null) {
					BinaryTree rightTree = new LinkedBinaryTree(root.rightChild);
					node = rightTree.findKey(value);
					if (node != null) {
						return node;
					} else {
						return null;
					}
				}
			}
		}
		return null;
	}