BST.py

#node with pointers to left and right children and a value (key) inside
class Node:
    def __init__(self, value):
        self.left = None
        self.right = None
        self.value = value

#insert a node to the left or right of a node
#maintaining the BST properties
def insert(root, node):
    #if there is no root, the root is equal to the node
    if root is None:
        root = node
    else:
        #if the number is bigger than root, move to the right
        if root.value < node.value:
            #if there is currently no node to the right, place node there
            if root.right is None:
                root.right = node
            else:
                #if there is a node there, start from that node and repeat process
                insert(root.right, node)
        #reach this if number is smaller than root (going left)
        else: 
            #if there is currently no node to the left, place node there
            if root.left is None:
                root.left = node
            else:
                #if there is a node there, start from that node and repeat process
                insert(root.left, node)

def inorderWalk(root):
    if root != None:
        inorderWalk(root.left)
        print(root.value)
        inorderWalk(root.right)

rootNode = Node(50)

insert(rootNode, Node(30))
insert(rootNode, Node(20))
insert(rootNode, Node(40))
insert(rootNode, Node(70))
insert(rootNode, Node(60))
insert(rootNode, Node(80))

inorderWalk(rootNode)