Complexity Classes: Introduction and Examples

This lecture introduces the concept of complexity classes by addressing the solvability of problems by algorithms and the classification of problems based on their difficulty. The instructor explains the notation for comparing functions and defines the classes P and NP, illustrating with examples of problems belonging to each class. The lecture explores how certain problems, such as subset sum problems, can be categorized within these complexity classes, leading to the famous P vs. NP problem. The instructor also presents examples of problems that are easy to solve within class P and demonstrates the complexity of verifying solutions for problems in class NP.