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:

Left View of a binary tree

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

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If you find anything incorrect or you feel that there is any better approach to solve the above problem, please write comment.
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  • Pintu Das

    Please check the height(Node root) method. I think the base case (root == null) should return -1 instead of 0;

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