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