Height of Binary Tree in DSA Javascript - Build from Scratch

Height of Binary Tree

📖 Scenario: You are working on a simple program to find the height of a family tree. Each person can have up to two children. The height tells us how many generations are in the family.

🎯 Goal: Build a binary tree representing a family and write code to find its height.

📋 What You'll Learn

Create a binary tree node class called TreeNode with value, left, and right properties

Create a binary tree with exactly 3 levels using TreeNode

Write a function called height that calculates the height of the binary tree

Print the height of the binary tree

💡 Why This Matters

🌍 Real World

Binary trees are used in many real-world applications like family trees, file systems, and decision-making processes.

💼 Career

Understanding tree structures and recursion is important for software development roles, especially in algorithms and data structure interviews.

1

Create TreeNode class and root node

Create a class called TreeNode with a constructor that takes value and sets left and right to null. Then create a root node called root with value 1.

DSA Javascript

class TreeNode {
  constructor(value) {
    // Your code here
  }
}

// Create root node
// Your code here

Hint

Remember to set left and right to null inside the constructor.

2

Add children to root to form 3 levels

Add two children to root: root.left with value 2 and root.right with value 3. Then add one child to root.left: root.left.left with value 4.

DSA Javascript

class TreeNode {
  constructor(value) {
    this.value = value;
    this.left = null;
    this.right = null;
  }
}

const root = new TreeNode(1);
// Add children to root and root.left
// Your code here

Hint

Assign new TreeNode objects to root.left, root.right, and root.left.left.

3

Write function to find height of binary tree

Write a function called height that takes a node and returns 0 if the node is null. Otherwise, return 1 + Math.max(height(node.left), height(node.right)).

DSA Javascript

class TreeNode {
  constructor(value) {
    this.value = value;
    this.left = null;
    this.right = null;
  }
}

const root = new TreeNode(1);
root.left = new TreeNode(2);
root.right = new TreeNode(3);
root.left.left = new TreeNode(4);

function height(node) {
  // Your code here
}

Hint

Use recursion to find the height of left and right subtrees, then add 1.

4

Print the height of the binary tree

Use console.log to print the height of the tree by calling height(root).

DSA Javascript

class TreeNode {
  constructor(value) {
    this.value = value;
    this.left = null;
    this.right = null;
  }
}

const root = new TreeNode(1);
root.left = new TreeNode(2);
root.right = new TreeNode(3);
root.left.left = new TreeNode(4);

function height(node) {
  if (node === null) {
    return 0;
  }
  return 1 + Math.max(height(node.left), height(node.right));
}

// Print the height of the tree
// Your code here

Hint

The height of this tree is 3 because it has 3 levels.