Print Left View of a given binary tree

Objective: In a Binary Tree, print left view of it

Input: A binary tree.

What is left View of a binary Tree

When just look at the tree from the left side , all the nodes you can see will be the left view of the tree.

Example:

Approach:

Method 1:

Traverse the tree from left to right
Print the first node you encounter
Take two variables , currentLevel=0 and nextLevel=1
As soon as you change level , change the currentLevel = nextLevel
Print only when current level<nextLevel so this way you will print only the first element
For rest of the nodes on the the level currentLevel and nextLevel are equal so it wont print

Method 2:

Do the Level order traversal and print the first node value

Complete Code:

Output:

METHOD 1:
5 10 20 45
METHOD 2 : Using Level Order, Left view
5 10 20 45