JavaScript Program to Find Smallest Number in a Linked List

Given a linked list, the task is to find the smallest number in a linked list in JavaScript. A “linked list” is a data structure to store data where each piece of information is connected to the next one, forming a chain. Each piece has its data and knows where to find the next piece. It’s a basic but useful method to organize and manage data.

Here, we have given a linked list, and the task is to find the smallest number within the linked list.

Examples:

Input: 3 -> 4 -> 1 -> 7 -> 5
Output: 1

Input: 2 -> 7 -> 5 -> 5 -> 8 -> 4
Output: 2

Iterative Approach to Find Smallest Number in a Linked List

This method iterates through the list, initializing the smallest variable with the head node’s data and updating it. We find a smaller value at the node’s data. This approach traverses the list once. So time taken by this method is linear.

Example: Print the smallest number in the linked list using iteative method (while loop).

Javascript

class Node {
    constructor(data) {
        this.data = data;
        this.next = null;
    }
}

class LinkedList {
    constructor() {
        this.head = null;
    }

    addNode(data) {

        const newNode = new Node(data);
        if (!this.head) {
            this.head = newNode;
        } else {
            let current = this.head;
            while (current.next) {
                current = current.next;
            }
            current.next = newNode;
        }
    }

    findSmallest() {
        if (!this.head) {
            return null;
        }

        let current = this.head;
        let smallest = current.data;

        while (current) {
            if (current.data < smallest) {
                smallest = current.data;
            }
            current = current.next;
        }

        return smallest;
    }
}

// Example
const linkedList = new LinkedList();
linkedList.addNode(3);
linkedList.addNode(1);
linkedList.addNode(4);
linkedList.addNode(2);

let smallest = linkedList.findSmallest();
console.log("Smallest number in the linked list:", smallest);

Output

Smallest number in the linked list: 1

Time Complexity: O(n)

Space Complexity: O(1)

Recursive Approach to Find Smallest Number in a Linked List

It is a recursive strategy to find the smallest number in a linked list using JavaScript. The “findSmallest” function looks at the current element, compares its value with the smallest value found in the rest of the list obtained through recursive calls, and updates if a smaller value is encountered.

This recursive process continues until the end of the list is reached. By breaking down the problem into smaller parts, this method efficiently explores the entire list, eventually finding the smallest number. It is one of the effective approach for solving this task.

Example: Recursive approach to print smallest number in the linked list in JavaScript.

Javascript

class Node {
    constructor(data) {
        this.data = data;
        this.next = null;
    }
}

class LinkedList {
    constructor() {
        this.head = null;
    }

    addNode(data) {

        const newNode = new Node(data);
        if (!this.head) {
            this.head = newNode;
        } else {
            let current = this.head;
            while (current.next) {
                current = current.next;
            }
            current.next = newNode;
        }
    }

    findSmallest(node = this.head) {
        if (!node) {
            return null;
        }

        const smallestInRest = this.findSmallest(node.next);

        if (smallestInRest !== null) {
            return Math.min(node.data, smallestInRest);
        }
        else {
            return node.data;
        }
    }
}

// Example
const linkedList = new LinkedList();
linkedList.addNode(7);
linkedList.addNode(5);
linkedList.addNode(4);
linkedList.addNode(3);

let smallest = linkedList.findSmallest();
console.log("Smallest number in the linked list :", smallest);

Output

Smallest number in the linked list : 3

Time Complexity: O(n)

Space Complexity: O(n)