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Commit af019f0

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Implemented LL-based Stack (#3 IP)
Implemented linked list style Stack. Created reusable Linked List Node.
1 parent da6fe2d commit af019f0

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5 files changed

+132
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5 files changed

+132
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‎Algorithms/README.md

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- [ ] Breadth First Search (BFS)
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- [ ] Depth First Search (DFS)
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## Resources
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## Resources
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- [Visualizing Data Structures & Algorithms](https://visualgo.net/en)

‎Data-Structures/Linked-Lists/NodeLL.ts

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export default class LinkedListNode<T> {
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private value: T;
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private next: LinkedListNode<T> | null;
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constructor(value: T) {
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this.value = value;
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this.next = null;
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}
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public setValue(value: T) {
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this.value = value;
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}
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public setNext(nextNode: LinkedListNode<T>) {
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this.next = nextNode;
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}
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public getValue(): T {
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return this.value;
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}
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public getNext(): LinkedListNode<T> | any {
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return this.next;
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}
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}

‎Data-Structures/Sequential/Queue.ts

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‎Data-Structures/Sequential/Stack.ts

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‎Data-Structures/Sequential/StackLL.ts

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import Node from '../Linked-Lists/NodeLL.ts';
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export default class StackLL<T> {
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private top: Node<T> | null;
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private bottom: Node<T> | null;
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private length: number;
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constructor() {
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this.top = null;
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this.bottom = null;
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this.length = 0;
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}
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public peek(): T | null {
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return this.top?.getValue() || null;
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}
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public push(value: T): boolean {
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const newNode = new Node<T>(value);
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if (!this.top) { // If stack is empty, initialize
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this.top = newNode;
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this.bottom = newNode;
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}
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else { // Else manipulate pointers
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newNode.setNext(this.top);
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this.top = newNode;
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}
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/* Challenge (Alternate Else Clause):
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* 1. How does the code below behave and why is it incorrect?
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* 2. What are the consequences to time complexity?
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*/
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// else {
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// this.top.setNext(newNode); // Else, set next node of LL to new value
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// this.top = this.top.getNext(); // And move 'top' pointer forward
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// }
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++this.length; // Increment length
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return true;
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}
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public pop(): T | null {
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if (!this.top) return null; // If empty stack, return null
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if (this.length === 1) {
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this.bottom = null;
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}
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const value = this.top.getValue(); // Retrieve top value of stack
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this.top = this.top.getNext(); // Move top pointer to next node
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// On line 46, the reference to the top most node of the stack is lost
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// The node is now floating in memory, waiting patiently for the garbage collector
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--this.length;
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return value;
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}
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}
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function printStack(stack: StackLL<any>) {
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console.log(JSON.stringify(stack));
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}
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function printPopStack(stack: StackLL<any>) {
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console.log('Popped:', stack.pop());
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}
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function printPeekStack(stack: StackLL<any>) {
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console.log('Peeking:', stack.peek());
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}
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//---------------------------------------------------------------------
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// ---------- MAIN PROGRAM ----------
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//---------------------------------------------------------------------
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if (import.meta.main) {
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const ATLA = new StackLL<string>();
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printPeekStack(ATLA);
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ATLA.push('Sokka');
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ATLA.push('Katara');
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printPeekStack(ATLA);
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ATLA.push('Aang');
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ATLA.push('Appa');
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printStack(ATLA);
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printPopStack(ATLA);
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printStack(ATLA);
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printPopStack(ATLA);
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printPopStack(ATLA);
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printPopStack(ATLA);
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printStack(ATLA);
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ATLA.push('Zuko');
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ATLA.push('Iroh');
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printStack(ATLA);
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// RUN: deno run Data-Structures/Sequential/StackLL.ts
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}

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