Question

Creat a python method for a binary tree class that has an inputted lookup value and will output if the lookup values exist within the Binary Tree by returning True or False. Exists within the binary tree -True. No exist within the binary tree - false.Test the method in your code

Answer 1

Following is the code snippet to Search a node in Binary Tree. In following code ifNodeExists is the required method, see comments for explanation. I have also added screen shot of my code execution.

# Function to create a new tree node 
class newNode: 

        # Constructor for newNode
        def __init__(node, nodeValue): 
                node.nodeValue = nodeValue 
                node.left = None
                node.right = None

# Function to check if the given node exists in it
# input parameter node is root node of binary tree
# input paramenter key means value to look for.
 
def ifNodeExists(node, key):

        if (node == None): 
                return False

        if (node.nodeValue == key): 
                return True

        # then recursively call ifNodeExists on left tree
        res1 = ifNodeExists(node.left, key) 
        # node found
        if res1:
                return True

        # Node not found in left node so now
        # recursively call ifNodeExists on right tree
        res2 = ifNodeExists(node.right, key) 

        return res2
        
# Main code
if __name__ == '__main__':
        root = newNode(0) 
        root.left = newNode(10) 
        root.left.left = newNode(30) 
        root.left.left.left = newNode(70) 
        root.left.right = newNode(40) 
        root.left.right.left = newNode(80) 
        root.left.right.right = newNode(90) 
        root.right = newNode(20) 
        root.right.left = newNode(50) 
        root.right.right = newNode(60) 
        
        # value to look for
        key = 20
        
        # adding messages as given in question
        if (ifNodeExists(root, key)): 
                print("Exists within the binary tree - True.")
        else:
                print("No exist within the binary tree - False.")