Big O notation is the most common metric for calculating time complexity. It describes the execution time of a task in relation to the number of steps required to complete it. A task can be handled using one of many algorithms, each of varying complexity and scalability over time.
Big O notation is a mathematical notation that describes the limiting behavior of a function when the argument tends towards a particular value or infinity.
With Big O notation, we use the size of the input, which we call " n." So we can say things like the runtime grows "on the order of the size of the input" ( O ( n ) O O) or "on the order of the square of the size of the input" ( O ( n 2 ) O(n^2) O(n2)).