Coding Challenge Day-33: Problem 2: Post-Order Traversal of Binary Tree

Hello! So I’m doing a coding challenge where I solve a few questions every day and thought of posting them here on my blog so that you guys can join the challenge too!

Welcome to Coding challenge Day 33: Problem 2! Be sure to post your answers, queries etc in the comments!

Problem : Post-Order Traversal of Binary Tree

Algorithm Logic:

1. Traverse the left subtree, i.e., call Postorder(left-subtree)
2. Traverse the right subtree, i.e., call Postorder(right-subtree)
3. Visit the root.

Solution:

package binary_tree;

public class PostOrder_Traversal {
	
static class Node{
		
		int data;
		Node left_child, right_child;
		
		public Node (int d){
			data=d;
			left_child= right_child=null;
		}
	}
	
	static class Binary_tree{
		Node root;
		
		public void add_left_node (Node parent_node, Node node){
			parent_node.left_child=node;
		}
		
		public void add_right_node (Node parent_node, Node node){
			parent_node.right_child= node;
		}
		
		public void postorder_traversal (Node node){
			if(node==null)
				return;
			
			postorder_traversal(node.left_child);
			postorder_traversal(node.right_child);
			System.out.print(node.data+ " ");
		}
	}
	
	public static void main (String [] args){
		Binary_tree t= new Binary_tree();
		
		t.root= new Node(10);
		
		Node node11= new Node(20);
		t.add_left_node(t.root, node11);
		
		Node node12= new Node(30);
		t.add_right_node(t.root, node12);
		
		Node node111= new Node(40);
		t.add_left_node(node11, node111);
		
		Node node112= new Node(50);
		t.add_right_node(node11, node112);
		
		t.postorder_traversal(t.root);
	}

}

Happy Learning!!