用python实现排序二叉树（中序）

class SortTree():

    def __init__(self):
        self.root = None

    def add(self, item):
        node = Node(item)

        cur = self.root

        if cur == None:
            self.root = node
            return

        while cur:

            if item > cur.item:

                if cur.right == None:
                    cur.right = node
                    break
                else:
                    cur = cur.right

            else:

                if cur.left == None:
                    cur.left = node
                    break
                else:
                    cur = cur.left

    def travle(self):

        cur = self.root

        q = [cur]
        while q:
            nd = q.pop(0)
            print(nd.item)
            if nd.left:
                q.append(nd.left)

            if nd.right:
                q.append(nd.right)
    def middle(self, root):

        if root == None:
            return

        self.middle(root.left)
        print(root.item)
        self.middle(root.right)



t = SortTree()

alist = [3, 8, 5, 7, 6, 2, 9, 4, 1]

for i in alist:
    t.add(i)

# t.travle()
t.middle(t.root)