BST Find Minimum Element in DSA Javascript - Build from Scratch

BST Find Minimum Element

📖 Scenario: You are working with a Binary Search Tree (BST) that stores numbers. You want to find the smallest number in this tree. This is useful when you want to quickly find the minimum value in a sorted structure.

🎯 Goal: Build a simple BST with given nodes and write code to find and print the minimum element in the BST.

📋 What You'll Learn

Create a BST with the exact nodes: 15, 10, 20, 8, 12, 17, 25

Create a function called findMin that finds the minimum value in the BST

Print the minimum value found by findMin

💡 Why This Matters

🌍 Real World

Finding minimum or maximum values quickly is useful in many applications like databases, search engines, and games where sorted data is stored in trees.

💼 Career

Understanding BST operations is important for software developers working with data structures, algorithms, and performance optimization.

1

Create BST Node class and build the tree

Create a class called Node with value, left, and right properties. Then create the BST by making nodes with these exact values and linking them to form this tree:

15 as root, 10 as left child of 15, 20 as right child of 15, 8 as left child of 10, 12 as right child of 10, 17 as left child of 20, 25 as right child of 20.

DSA Javascript

// Create Node class and build the BST with given nodes
// Your code here

Hint

Define a class with constructor for value, left, and right. Then create nodes and link them as left or right children exactly as described.

2

Create a function to find the minimum value

Create a function called findMin that takes the root node of the BST as input. It should return the smallest value by moving left until no more left child exists.

DSA Javascript

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

const root = new Node(15);
root.left = new Node(10);
root.right = new Node(20);
root.left.left = new Node(8);
root.left.right = new Node(12);
root.right.left = new Node(17);
root.right.right = new Node(25);

// Create function findMin(root) to find minimum value
// Your code here

Hint

Start from root and keep moving to the left child until left is null. Then return the current node's value.

3

Call the function to find minimum

Call the findMin function with root as argument and store the result in a variable called minValue.

DSA Javascript

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

const root = new Node(15);
root.left = new Node(10);
root.right = new Node(20);
root.left.left = new Node(8);
root.left.right = new Node(12);
root.right.left = new Node(17);
root.right.right = new Node(25);

function findMin(root) {
    let current = root;
    while (current.left !== null) {
        current = current.left;
    }
    return current.value;
}

// Call findMin(root) and store result in minValue
// Your code here

Hint

Use const minValue = findMin(root); to call the function and save the result.

4

Print the minimum value

Print the value stored in minValue using console.log.

DSA Javascript

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

const root = new Node(15);
root.left = new Node(10);
root.right = new Node(20);
root.left.left = new Node(8);
root.left.right = new Node(12);
root.right.left = new Node(17);
root.right.right = new Node(25);

function findMin(root) {
    let current = root;
    while (current.left !== null) {
        current = current.left;
    }
    return current.value;
}

const minValue = findMin(root);

// Print minValue using console.log
// Your code here

Hint

Use console.log(minValue); to print the minimum value.