BST Find Minimum Element in DSA Typescript - 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 know the minimum value stored in a sorted structure.

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

📋 What You'll Learn

Create a BST node class with value, left, and right properties

Manually build a BST by linking nodes with exact values

Write a function findMin that finds the minimum value in the BST

Print the minimum value found

💡 Why This Matters

🌍 Real World

Finding the minimum value in a BST is useful in databases, search engines, and any system that needs quick access to sorted data.

💼 Career

Understanding BST operations like finding minimum or maximum values is essential for software engineers working with data structures, algorithms, and performance optimization.

1

Create BST Node Class and Build Tree

Create a class called TreeNode with a constructor that takes a value of type number. It should have public properties value, left, and right initialized to null. Then create three nodes: root with value 10, leftChild with value 5, and rightChild with value 15. Link root.left to leftChild and root.right to rightChild.

DSA Typescript

// Your code here

Hint

Remember to create a class with value, left, and right properties. Then create nodes and link them properly.

2

Add a Function to Find Minimum Value

Create a function called findMin that takes a parameter node of type TreeNode | null and returns a number. Inside the function, use a while loop to move to the left child until node.left is null. Return the value of the last node reached.

DSA Typescript

class TreeNode {
    value: number;
    left: TreeNode | null;
    right: TreeNode | null;

    constructor(value: number) {
        this.value = value;
        this.left = null;
        this.right = null;
    }
}

const root = new TreeNode(10);
const leftChild = new TreeNode(5);
const rightChild = new TreeNode(15);

root.left = leftChild;
root.right = rightChild;

// Your code here

Hint

Use a while loop to go left until no more left child exists, then return that node's value.

3

Call the Function to Find Minimum

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

DSA Typescript

class TreeNode {
    value: number;
    left: TreeNode | null;
    right: TreeNode | null;

    constructor(value: number) {
        this.value = value;
        this.left = null;
        this.right = null;
    }
}

const root = new TreeNode(10);
const leftChild = new TreeNode(5);
const rightChild = new TreeNode(15);

root.left = leftChild;
root.right = rightChild;

function findMin(node: TreeNode | null): number {
    while (node && node.left !== null) {
        node = node.left;
    }
    return node ? node.value : -1;
}

// Your code here

Hint

Call findMin with root and save the result in minValue.

4

Print the Minimum Value

Print the value of the variable minValue using console.log.

DSA Typescript

class TreeNode {
    value: number;
    left: TreeNode | null;
    right: TreeNode | null;

    constructor(value: number) {
        this.value = value;
        this.left = null;
        this.right = null;
    }
}

const root = new TreeNode(10);
const leftChild = new TreeNode(5);
const rightChild = new TreeNode(15);

root.left = leftChild;
root.right = rightChild;

function findMin(node: TreeNode | null): number {
    while (node && node.left !== null) {
        node = node.left;
    }
    return node ? node.value : -1;
}

const minValue = findMin(root);

// Your code here

Hint

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