Day 3 is all about thinking like a developer. We’ll explore core data structures like stacks and queues using lists, and practice breaking problems into input, process, and output. You’ll work with libraries like random, math, and numpy, and dive into string logic and array manipulation. Live exercises include building a password generator, a constrained randomizer, and finding the most common word in a sentence. We’ll also introduce recursion with simple examples and visualize how stack flow works in debugging.