算法（Algorithm）是指解题方案的准确而完整的描述，是一系列解决问题的清晰指令，算法代表着用系统的方法描述解决问题的策略机制。也就是说，能够对一定规范的输入，在有限时间内获得所要求的输出。如果一个算法有缺陷，或不适合于某个问题，执行这个算法将不会解决这个问题。不同的算法可能用不同的时间、空间或效率来完成同样的任务。一个算法的优劣可以用空间复杂度与时间复杂度来衡量。(Algorithm (Algorithm) is to point to the problem solving scheme of accurate and complete descr iption, is a set of clear instructions to solve the problem, the Algorithm represents the describe the strategy to solve the problem using the method of system mechanism.That is to say, to a certain specification of input, obtain the required output in a limited time.If an algorithm is flawed, or not suitable for a particular problem, carry out the algorithm will not solve the problem.Different algorithms may use different time, space, or efficiency to accomplish the same tasks.The pros and cons of an algorithm can be used to measure the space complexity and time complexity.)