CS50 Fall 2025 - Lecture 0 - Scratch (live, unedited)

In this introductory lecture of Harvard's CS50 course, David Malan explores the fundamentals of computer science, emphasizing problem-solving and computational thinking rather than just programming skills. He discusses the impact of AI on programming, highlighting its potential to assist but not replace human understanding of core concepts. The lecture covers how computers represent information using binary code, progressing from basic number representation to encoding text, images, and sound. Malan also touches on algorithms and their efficiency, illustrating with examples like searching a phone book, and introduces pseudocode as a tool for planning solutions. The lecture further includes a demonstration of Scratch, a visual programming language, to illustrate basic programming concepts.