Theory of Computations!

Theory of computation (TOC) is a branch of Computer Science that is concerned with how problems can be solved using algorithms and how efficiently they can be solved. Real-world computers perform computations that by nature run like mathematical models to solve problems in systematic ways.
In theoretical computer science and mathematics, the theory of computation is the branch that deals with what problems can be solved on a model of computation, using an algorithm, how efficiently they can be solved or to what degree