Plagiarism in solutions of programming tasks in distance learning

Source code plagiarism in students solutions of programming tasks is a serious problem, especially important in distance learning. Naturally, it should be prevented, but publicly available code plagiarism detection tools are not fully adjusted to this purpose. This paper proposes the specific approach to detecting code duplicates. This approach is based on adapting of detection process to characteristics of programming tasks and comprise of freshly developed detecting tools, which could be configured and tuned to fit individual features of the programming task. Particular attention is paid to the possibility of an automatic elimination of duplicate codes from the set of all solutions. As a minimum, this requires the rejection of false-positive duplicates, even for simple, schematic tasks. The case in the use of tools is presented in this context. The discussion is illustrated by applying of proposed tools to duplicates detection in the set of actual, real-life, codes written in Java programming language.