说明：  聚类算法：最短距离算法。对给定的数据集进行自底向上的层次的分解，直到某种条件满足而已。缺陷在于一旦一个步骤完成，它就不能被撤消这个严格的规定是有用的，由于不用担心组合数目的不同选择，计算代价会较小。
(Clustering Algorithm: the shortest distance algorithm. For a given data set to the level of bottom-up decomposition, until certain conditions are fulfilled it. Once the defect is a step towards completion, it can not be undone this strict requirement is useful to not have to worry about as a result of combination of the number of different options for calculating the price will be smaller.)