Create a Binary Tree Manually in DSA Javascript - Build from Scratch

Create a Binary Tree Manually

📖 Scenario: You are building a simple binary tree by manually creating nodes and linking them. This is like making a family tree by connecting parents and children step by step.

🎯 Goal: Create a binary tree by defining nodes as objects and linking them as left and right children. Then print the tree structure in a readable format.

📋 What You'll Learn

Create a node object with value, left, and right properties

Manually link nodes to form a binary tree

Write a function to print the tree nodes in pre-order traversal

Print the tree nodes in the correct order

💡 Why This Matters

🌍 Real World

Binary trees are used in many places like organizing data, searching quickly, and making decisions step-by-step.

💼 Career

Understanding how to build and traverse trees is important for software development, especially in areas like databases, file systems, and algorithms.

1

Create the root node

Create a variable called root that is an object with value set to 10, and left and right set to null.

DSA Javascript

// Your code here

Hint

Think of the root as the main node with no children yet.

2

Add left and right children to root

Create two variables called leftChild and rightChild. Set leftChild to an object with value 5 and null children. Set rightChild to an object with value 15 and null children. Then assign root.left to leftChild and root.right to rightChild.

DSA Javascript

const root = { value: 10, left: null, right: null };
// Your code here

Hint

Link the children to the root by assigning them to root.left and root.right.

3

Add a left child to the left child node

Create a variable called leftLeftChild as an object with value 3 and null children. Assign leftChild.left to leftLeftChild.

DSA Javascript

const root = { value: 10, left: null, right: null };
const leftChild = { value: 5, left: null, right: null };
const rightChild = { value: 15, left: null, right: null };
root.left = leftChild;
root.right = rightChild;
// Your code here

Hint

Link the new node as the left child of the leftChild node.

4

Print the tree nodes in pre-order

Write a function called printPreOrder that takes a node and prints its value, then recursively prints the left child, then the right child. Call printPreOrder(root) to print all nodes.

DSA Javascript

const root = { value: 10, left: null, right: null };
const leftChild = { value: 5, left: null, right: null };
const rightChild = { value: 15, left: null, right: null };
root.left = leftChild;
root.right = rightChild;
const leftLeftChild = { value: 3, left: null, right: null };
leftChild.left = leftLeftChild;

// Your code here

Hint

Pre-order means print current node, then left subtree, then right subtree.