说明：  码剽窃是程序设计课程中经常出现的一种作弊行为，检测剽窃的源代码，验证学生程序作业的原创性在教学中很重要．程序代码的相似度度量是剽窃检测的关键技术．
(Code plagiarism is one kind of cheat behavior,which appears frequently in the programming curriculum．Detection of source code plagiarism is important to verify the originality of students’ project works．)