Web-Expert

 Arrays and linked lists both store ordered collections of data, but they do it very differently under the hood — and that difference shows up constantly in interviews and in real performance bugs. Here's the easy-to-understand version. Arrays: Data Sitting Next to Each Other An array stores its elements in one continuous block of memory. Because every element is the same fixed distance apart, the computer can jump straight to any index instantly. const fruits = ["apple", "banana", "cherry"]; console.log(fruits[1]); // "banana" — instant lookup, O(1) Strength: reading by index is O(1) — constant time. Weakness: inserting or removing from the middle (or start) means shifting every element after it, which is O(n) . Linked Lists: Data Connected by Pointers A linked list stores each element (called a node ) separately in memory, with each node holding a pointer to the next one. There's no requirement that they sit next to each ...

 Stacks and queues are two of the simplest data structures in DSA, and also two of the most useful — browser history, undo/redo, task scheduling, and breadth-first search all lean on them. The easiest way to understand both is through a real-life analogy. Stack: Last In, First Out (LIFO) Picture a stack of plates. You can only add a plate to the top, and you can only remove the plate that's currently on top. The last plate you put down is the first one you pick back up. class Stack { constructor() { this.items = []; } push(item) { this.items.push(item); // add to the top } pop() { return this.items.pop(); // remove from the top } peek() { return this.items[this.items.length - 1]; } } const stack = new Stack(); stack.push(1); stack.push(2); stack.push(3); console.log(stack.pop()); // 3 — the last one in comes out first Real-world examples: the "undo" button in an editor, the browser's back button, and how your program tracks fu...