An algorithm is a well-defined sequence of instructions or rules that provides a solution to a specific problem or task. Originating from ancient civilizations, algorithms have evolved through centuries and are now integral to modern computing. They are designed using techniques such as divide-and-conquer and are evaluated for efficiency using measures like big O notation. Algorithms can be represented in various forms like pseudocode, flowcharts, or programming languages. They are executed by translating them into a language that computers can understand, with the speed of execution dependent on the instruction set used. Algorithms can be classified based on their implementation or design paradigm, and their efficiency can significantly impact processing time. Understanding and using algorithms effectively is crucial in fields like ordinateur[2] science and intelligence artificielle[1].
Au mathematics et computer science, an algorithme (/ˈælɡərɪðəm/ ⓘ) is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a calcul. Algorithms are used as specifications for performing calculations et data processing. More advanced algorithms can use conditionals to divert the code execution through various routes (referred to as automated decision-making) and deduce valid inferences (referred to as automated reasoning), achieving automation eventually. Using human characteristics as descriptors of machines in metaphorical ways was already practiced by Alan Turing with terms such as "memory", "search" and "stimulus".
In contrast, a heuristic is an approach to problem solving that may not be fully specified or may not guarantee correct or optimal results, especially in problem domains where there is no well-defined correct or optimal result. For example, social media recommender systems rely on heuristics in such a way that, although widely characterized as "algorithms" in 21st century popular media, cannot deliver correct results due to the nature of the problem.
As an effective method, an algorithm can be expressed within a finite amount of space and time and in a well-defined formal language for calculating a function. Starting from an initial state and initial input (perhaps empty), the instructions describe a computation that, when executed, proceeds through a finite number of well-defined successive states, eventually producing "output" and terminating at a final ending state. The transition from one state to the next is not necessarily deterministic; some algorithms, known as randomized algorithms, incorporate random input.