algorithm

Algorithm refers to an accurate and complete description of the solution scheme, which is a series of clear instructions for solving problems. Algorithm represents a systematic approach to describing the strategy mechanism for solving problems. In other words, the required output can be obtained within a limited time for a certain standard input. If an algorithm has defects or is not suitable for a problem, executing the algorithm will not solve the problem. Different algorithms may use different time, space or efficiency to complete the same task. The advantages and disadvantages of an algorithm can be measured by space complexity and time complexity. The instructions in the algorithm describe a calculation. When it runs, it can start from an initial state and (possibly empty) initial input, go through a series of limited and clearly defined states, and finally produce output and stop at an end state. The transition from one state to another is not necessarily certain. Some algorithms, including randomization algorithm, include some random inputs. The concept of formal algorithm is partly derived from trying to solve the decision problem proposed by Hilbert, and then trying to define effective computability or effective method. These attempts include the recursive function proposed by Kurt Godel, Jacques Herbrand and Stephen Cole Klein in 1930, 1934 and 1935 respectively, the λ calculus proposed by Alonzo Church in 1936, and the Turing machine proposed by Emil Leon Post in 1936 and Alan Turing in 1937. Even at present, there are still cases where intuitive ideas are difficult to define as formal algorithms.