说明：  很多算法的每一个计算步骤都是固定的，而在下面我们要讨论的概率算法，允许算法在执行的过程中随机选择下一个计算步骤。许多情况下，当算法在执行过程中面临一个选择时，随机性选择常比最优选择省时。因此概率算法可在很大程度上降低算法的复杂度。
(Many algorithms each calculation steps are fixed, while in the following we are going to discuss the probability of algorithm, permit the implementation of algorithm in the process of calculating the next random selection steps. Many cases, when the algorithm in the implementation process faced with a choice, random choice of regular time-saving than the optimal choice. Therefore the probability of algorithm can be reduced to a large extent the complexity of algorithms.)