type treeNode struct {
    Val string 	    //節(jié)點值
    left *treeNode 	//左節(jié)點
    right *treeNode //右節(jié)點
}

// 創(chuàng)建節(jié)點
func CreateBinaryTree(data string) *treeNode {
    return &treeNode{data, nil, nil}
}

// 插入節(jié)點
func (node *treeNode) Insert(n *treeNode, data string) bool {
    cur := n
    for cur != nil {
        if cur.Val < data {
            if cur.Right != nil {
                cur = cur.Right
            } else {
                cur.Right = CreateBinaryTree(data)
                return true
            }
        } else {
            if cur.Left != nil {
                cur = cur.Left
            } else {
                cur.Left = CreateBinaryTree(data) 
                return true
            }
        }
    }
    return false
}

func preOrder(root *bt) {
	if root != nil {
		fmt.Print(root.Val, " ")
		preOrder(root.Left)
		preOrder(root.Right)
	}
}

func inOrder(root *bt) {
	if root != nil {
		inOrder(root.Left)
		fmt.Print(root.Val, " ")
		inOrder(root.Right)
	}
}

func posOrder(root *bt) {
	if root != nil {
		posOrder(root.Left)
		posOrder(root.Right)
		fmt.Print(root.Val, " ")
	}
}