The difficult of Average case Analysis of an Algorithm In order to perform a probabilistic analysis,we must use knowledge of,or make assumptions about,the distribution of the inputs. Then we analyze our algorithm,computing an average-case running time,where we take the average over the distribution of the possible inputs.Thus we are,in effect,averaging the running time over all possible inputs.When reporting such a running time,we will refer to it as the average-case running time. 输入数据的分布特性假设失败，必定导致平均运行时间分析的失败The difficult of Average case Analysis of an Algorithm 输入数据的分布特性假设失败，必定导致平均运行时间分析的失败