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import { ILinkedList, NodeType, Node } from "./helper.ts";

export class SinglyLinkedList implements ILinkedList {	head: null|NodeType	tail: null|NodeType	size: number
	constructor() {		this.head = null		this.tail = null		this.size = 0	}
	insertInHead(data: string) {		if (this.head === null) {			const newNode = new Node(data);			this.head = newNode			this.tail = newNode			this.size++;			return true;		}
		const currentNode = this.head		this.head = new Node(data)		this.head.next = currentNode		if (currentNode.next === null) {			this.tail = currentNode		}		this.size++
		return true;	}
	insertInTail(data: string) {		if (this.head === null) {			const newNode = new Node(data);			this.head = newNode			this.tail = newNode			this.size++;			return true;		}
		let currentNode = this.head		while ( currentNode !== null ) {			const newItem = new Node(data);			this.tail = newItem
			if (currentNode.next === null) {				currentNode.next = newItem
				this.size++;				return true;			}			currentNode = currentNode.next		}
		return false;	}
	insertInPositonX(data: string, position: number) {		if (position === 0) {			console.error("Use `insertAtHead()` method to insert data at Head.");			return false;		} else if (position === this.size) {			console.error("Use `insertAtTail()` method to insert data at Tail.");			return false;		} else if (position > this.size && position != this.size + 1) {			console.error(`Out of range. Size of the linkedList is ${this.size}`);			return false;		}			let prevNode: NodeType = null;		let currentNode = this.head		let count = 0		while (currentNode !== null) {			if (count === position) {				prevNode!.next = new Node(data)				prevNode!.next.next = currentNode				this.size++			}				prevNode = currentNode			currentNode = currentNode.next			count++		}
		return true;	}
	getFromHead() {		if (this.head === null) {			return null		}
		return this.head.value;	}
	getFromTail() {		if (this.tail === null) {			return null		}
		return this.tail.value	}
	printValues() {		let currentNode = this.head		while (currentNode !== null) {			console.log(currentNode.value);			currentNode = currentNode.next		}	}}