Resumen
Programming education for beginners often employs online judges. Although this helps improve coding skills, students may not obtain sufficient educational effects if the assignment is too difficult. Instead of presenting a model answer to an assignment, this paper proposes an approach to provide students with problems that have content and answer source code similar to the assignment. The effectiveness of our approach is evaluated via an intervention experiment in a university lecture course. The improvement in the number of correct answers is statistically significant compared to the same course offered in a different year without the proposed system. Therefore, the proposed approach should aid in the understanding of an assignment and enhance the educational effect.