Question

A binary search tree(BST) relies on the property that keys that are less than the parent are found in the left subtree, and keys that are greater than the parent are found in the right subtree.

Implement a BST with the following basic components

1. Create a BST for a list of data (= 10, 5, 8, 2, 4, 12, 11, 4, 9, 15)[ use insert(value) function\

2. Print the values in inorder, preorder, and post order

Please code in Python 3

Answer 1

Code for the above question in python :

    class Node:
        def __init__(self,key):
            self.left = None
            self.right = None
            self.val = key
   
    # A utility function to insert a new node with the given key
    def insert(root,node):
        if root is None:
            root = node
        else:
            if root.val < node.val:
                if root.right is None:
                    root.right = node
                else:
                    insert(root.right, node)
            else:
                if root.left is None:
                    root.left = node
                else:
                    insert(root.left, node)
   
    # A function to do inorder tree traversal
    def printInorder(root):
   
        if root:
   
            # First recur on left child
            printInorder(root.left)
   
            # then print the data of node
            print(root.val,end=' ')
   
            # now recur on right child
            printInorder(root.right),
   
   
   
    # A function to do postorder tree traversal
    def printPostorder(root):
   
        if root:
   
            # First recur on left child
            printPostorder(root.left)
   
            # the recur on right child
            printPostorder(root.right)
   
            # now print the data of node
            print(root.val,end=' '),
   
   
    # A function to do preorder tree traversal
    def printPreorder(root):
   
        if root:
   
            # First print the data of node
            print(root.val,end=' ') ,
   
            # Then recur on left child
            printPreorder(root.left)
   
            # Finally recur on right child
            printPreorder(root.right)
   
    # data = 10, 5, 8, 2, 4, 12, 11, 4, 9, 15
   
    # Driver code
    root = Node(10)
    insert(root,Node(5))
    insert(root,Node(8))
    insert(root,Node(2))
    insert(root,Node(4))
    insert(root,Node(12))
    insert(root,Node(11))
    insert(root,Node(4))
    insert(root,Node(9))
    insert(root,Node(15))
   
   
    print("Preorder traversal of binary tree is")
    printPreorder(root)
   
    print("\nInorder traversal of binary tree is")
    printInorder(root)
   
    print("\nPostorder traversal of binary tree is")
    printPostorder(root)

Screenshot of tested code:

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