In [3]:

    

class Node:
    def __init__(self, value=None, left=None, right=None):
        self.value = value
        self.left = None
        self.right = None


    

In [91]:

    

class BinarySearchTree:
    def __init__(self, value=None):
        self.root = Node(value)
    
    def insert(self, root, value):
        if root == None:
            return Node(value)
        if value < root.value:
            if root.left == None:
                root.left = self.insert(root.left, value)
            else:
                self.insert(root.left, value)
        else:
            if root.right == None:
                root.right = self.insert(root.right, value)
            else:
                self.insert(root.right, value)
    
    def preorder(self, root=None):
        """Root, Left, Right"""
        if root == None:
            root = self.root
            return
        print(root.value)
        self.preorder(root.left)
        self.preorder(root.right)
    
    def inorder(self, root=None):
        """Left, Root, Right"""
        if root == None:
            root = self.root
            return
        self.inorder(root.left)
        print(root.value)
        self.inorder(root.right)
            
    def postorder(self, root=None):
        """Left, Right, Root"""
        if root == None:
            root = self.root
            return
        self.postorder(root.left)
        self.postorder(root.right)
        print(root.value)
    
    def bfs(self, root=None):
        if root == None:
            root = self.root
        queue = []
        visited = set()
        print(root.value)
        visited.add(root)
        queue.append(root)
        
        while len(queue) != 0:
            curr = queue.pop(0)
            adjacent = [curr.left, curr.right]
            for n in adjacent:
                if n == None:
                    return
                if n not in visited:
                    print(n.value)
                    visited.add(n)
                    queue.append(n)


    

In [92]:

    

b = BinarySearchTree(100)
b.insert(b.root, 10)
b.insert(b.root, 101)
b.insert(b.root, 9)


    

In [93]:

    

b.preorder(b.root)


    

    




100
10
9
101

In [94]:

    

b.inorder(b.root)


    

    




9
10
100
101

In [95]:

    

b.postorder(b.root)


    

    




9
10
101
100

In [96]:

    

b.bfs()


    

    




100
10
101
9

In [ ]: