Complexity classes

Complexity classes are categories that classify computational problems based on how difficult they are to solve. For example, "P" includes problems that can be solved quickly by computers, while "NP" includes problems for which solutions can be checked quickly, even if finding them may take longer. There's also "NP-complete," a group of challenging problems within NP that are believed to be as hard as the hardest problems in NP. Understanding these classes helps computer scientists gauge the feasibility of solving different problems, especially as data sizes grow.