Question

Can you help me with python question:

Implement the function isBinarySearchTree(root), which returns True if the binary tree passed to it is a valid binary search tree.

I've provided a simple TreeNode class, and the beginnings of isBinarySearchTree(root).

class TreeNode:
'''Node for a simple binary tree structure'''
def __init__(self, value, left, right):
self.value = value
self.left = left
self.right = right

  
def isBinarySearchTree(tree):

Answer 1

Program:

# Python program to check if a binary tree is BinarySearchTree or not

INT_MAX = 9999999999     #instalize maximum  and minimum values

INT_MIN = -9999999999

class TreeNode:          # This class is to assign data to node

  def __init__(self, value):

    self.data = value

    self.left = None

    self.right = None

def isBinarySearchTree(node, mini, maxi):      # method is used to find binary tree or not

  if node is None:

    return True

  if node.data < mini or node.data > maxi:     # this condition is to check data is in right order or not

    return False

  # this is for recursive calling of both left and right subtree of a tree

  return (isBinarySearchTree(node.left, mini, node.data -1) and isBinarySearchTree(node.right, node.data+1, maxi))

# Here we gave inputs to the trees

root = TreeNode(4)

root.left = TreeNode(2)

root.right = TreeNode(5)

root.left.left = TreeNode(1)

root.left.right = TreeNode(3)

isBinarySearchTree(root,INT_MIN, INT_MAX)    # here we calling the function to check wether it is binary search tree or not