档案日期2016的24

编辑距离（Edit Distance），也称Levenshtein距离，是指由一个字符串转换为另一个字符串所需的最少编辑次数。

下面的代码摘自org.apache.commons.lang.StringUtils

用法示例：

StringUtils.getLevenshteinDistance(null, *)             = IllegalArgumentException
StringUtils.getLevenshteinDistance(*, null)             = IllegalArgumentException
StringUtils.getLevenshteinDistance("","")               = 0
StringUtils.getLevenshteinDistance("","a")              = 1
StringUtils.getLevenshteinDistance("aaapppp", "")       = 7
StringUtils.getLevenshteinDistance("frog", "fog")       = 1 ...

题目描述：

LeetCode 357. Count Numbers with Unique Digits

Given a non-negative integer n, count all numbers with unique digits, x, where 0 ≤ x < 10ⁿ.

Example:

Given n = 2, return 91. (The answer should be the total numbers ...