Time and Space Complexity Fundamentals

"It's not enough to write code that works. Great engineers write code that works **well." Why Does This Even Matter? Imagine you're building a contact search feature for a messaging app. You write the code, it works perfectly — on your laptop with 50 test contacts. Then the app launches. Users have 10,000 contacts. Search slows down. You get 50,000 users. The app crashes under load. The CEO is furious. The code was correct, but it wasn't efficient. This is exactly the problem...