Left View of Binary Tree Python

PROGRAM TO PRINT LEFT VIEW OF A BINARY TREE

class Node:

 

    # Constructor to create a new node

    def __init__(self, data):

        self.data = data

        self.left = None

        self.right = None

 

 

# Recursive function pritn left view of a binary tree

def leftViewUtil(root, level, max_level):

     

    # Base Case

    if root is None:

        return

 

    # If this is the first node of its level

    if (max_level[0] < level):

        print "% d\t" %(root.data),

        max_level[0] = level

 

    # Recur for left and right subtree

    leftViewUtil(root.left, level + 1, max_level)

    leftViewUtil(root.right, level + 1, max_level)

 

 

# A wrapper over leftViewUtil()

def leftView(root):

    max_level = [0]

    leftViewUtil(root, 1, max_level)

 

 

# Driver program to test above function

root = Node(12)

root.left = Node(10)

root.right = Node(20)

root.right.left = Node(25)

root.right.right = Node(40)

 

leftView(root)




OUTPUT:

12      10      25

CREDITS: https://www.geeksforgeeks.org/print-left-view-binary-tree/