CS50x 2026 - Lecture 3 - Algorithms

The lecture explores fundamental computer science concepts, focusing on algorithms for searching and sorting data. It begins with an interactive demonstration of an algorithm to count attendees, illustrating the efficiency gains from divide-and-conquer strategies. The discussion covers linear and binary search algorithms, highlighting trade-offs between speed and data organization. Key points include the introduction of big O notation for analyzing algorithm efficiency and a practical demonstration of linear search in C. The lecture then transitions to sorting algorithms, comparing selection sort and bubble sort, and introduces recursion as a powerful programming technique, exemplified by a recursive implementation of merge sort. The session concludes with a visualization comparing the performance of selection sort, bubble sort, and merge sort, emphasizing merge sort's superior efficiency.