实现LV距离算法，可用于字符串等相似度的应用计算，是相似度的核心算法实现，共分7步-LV distance algorithm to achieve, can be used to calculate the string so the application of similarity is the similarity of the core algorithm, is divided into 7 steps

验证码识别，字符串相似度算法（编辑距离算法 Levenshtein Distance）-Verification code identification, string similarity algorithm (edit Distance algorithm Levenshtein Distance)