# Big O Notation

Big O Notation, also known as Landau notation or asymptotic notation, is the measurement of an algorithm run time and memory usage. A programmer must always consider the worst case scenario of an algorithm when implementing e-commerce web-based applications. An algorithm that takes a considerable amount of time to be executed by the server is something to be avoided. The analysis of complex algorithm has an order function that shows their measurement of run time and memory usage. Programmers most often try to implement an algorithm that has linear order function O(n) where n represent n sub-problem in the problem domain. But that is that the case when it come to implementing complex system that have an exponential array of sub problems. Although the architectural design of the Central Process Unit (CPU) of has improved speed exponential each year, the complexity of computation for some of the problems being tackled these days, such as pattern recognition algorithms, adaptive algorithms, and algorithm to simulate the neural network of the human cerebral, have an infinity time complexity order function according the big O notation. The number of recursion of find n to the power of n O(n!) combinatorial of possible outcome require insurmountable processing time.