@m3rashid/dsa-js/structures/linked-list.js

A data-structures and algorithms library for node and browser written in typescript. Inspired from C++ standard library

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.test = exports.LinkedList = exports.LinkedListNode = void 0;
class LinkedListNode {
    constructor(data) {
        this._data = data;
        this._next = null;
    }
}
exports.LinkedListNode = LinkedListNode;
class LinkedList {
    constructor() {
        this._head = null;
        this._size = 0;
    }
    insertAtBeginning(data) {
        const node = new LinkedListNode(data);
        node._next = this._head;
        this._head = node;
        this._size++;
        return true;
    }
    insertAtEnd(data) {
        const node = new LinkedListNode(data);
        let current = this._head;
        if (!current)
            throw new Error('No HEAD of Linked List initialized');
        while (current._next)
            current = current._next;
        current._next = node;
        this._size++;
        return true;
    }
    insertAt(data, index) {
        if (index < 0 || index > this._size)
            throw new Error('Index out of range');
        if (index === 0) {
            this.insertAtBeginning(data);
            return false;
        }
        const node = new LinkedListNode(data);
        let current = this._head;
        let previous;
        let count = 0;
        while (count < index) {
            previous = current;
            if (!current)
                throw new Error('Index out of bounds');
            current = current._next;
            count++;
        }
        node._next = current;
        if (!previous)
            throw new Error('No HEAD of Linked List initialized');
        previous._next = node;
        this._size++;
        return true;
    }
    removeFromBeginning() {
        if (this._size === 0)
            return false;
        //move head to next node
        if (!this._head)
            throw new Error('No HEAD of Linked List initialized');
        this._head = this._head._next;
        this._size--;
        return true;
    }
    removeFromEnd() {
        if (this._size === 0)
            throw new Error('No HEAD of Linked List initialized');
        let current = this._head;
        let previous;
        if (!current)
            throw new Error('No HEAD of Linked List initialized');
        while (current._next) {
            previous = current;
            current = current._next;
        }
        if (!previous)
            throw new Error('No HEAD of Linked List initialized');
        previous._next = null;
        this._size--;
        return true;
    }
    removeAt(index) {
        if (index < 0 || index >= this._size)
            throw new Error('Index out of range');
        if (index === 0) {
            this.removeFromBeginning();
            return true;
        }
        let current = this._head;
        let previous;
        let count = 0;
        while (count < index) {
            if (!current)
                throw new Error('Index out of bounds');
            previous = current;
            current = current._next;
            count++;
        }
        if (!previous || !current)
            throw new Error('No HEAD of Linked List initialized');
        previous._next = current._next;
        this._size--;
        return true;
    }
    indexOfFirst(data) {
        let current = this._head;
        let count = 0;
        while (current) {
            if (current._data === data)
                return count;
            current = current._next;
            count++;
        }
        return -1;
    }
    indexOfLast(data) {
        let current = this._head;
        let count = 0;
        let index = -1;
        while (current) {
            if (current._data === data)
                index = count;
            current = current._next;
            count++;
        }
        return index;
    }
    isEmpty() {
        return this._size === 0;
    }
    size() {
        return this._size;
    }
    printList() {
        let current = this._head;
        let list = '';
        list += '[';
        while (current) {
            list += current._data;
            if (current._next)
                list += ',';
            current = current._next;
        }
        list += ']';
        console.log(list);
    }
    reverse() {
        let current = this._head;
        let previous = null;
        let next = null;
        while (current) {
            next = current._next;
            current._next = previous;
            previous = current;
            current = next;
        }
        this._head = previous;
    }
}
exports.LinkedList = LinkedList;
//sample code to test the linked list
const test = () => {
    const list = new LinkedList();
    list.insertAtBeginning(1); // [1]
    list.insertAtBeginning(2); // [2,1]
    list.insertAtEnd(5); // [2,1,5]
    list.insertAtEnd(6); // [2,1,5,6]
    list.insertAt(7, 2); // [2,1,7,5,6]
    list.removeFromBeginning(); // [1,7,5,6]
    list.printList(); // [2,7,5,6]
    list.reverse(); // [6,5,7,2]
    list.printList(); // [6,5,7,2]
};
exports.test = test;