Abstract:

According to Jeannette Wing [1], the computational thinking should be a fundamental skill for all humans, not just computer scientists. Therefore, we need to nurture this type of pupils’ thinking. But there is no prevalent way of doing it. Various scientists and educators use different approaches - using programming languages, theoretical tasks or informatics competitions.

In particular the use of informatics competitions is an interesting approach. Tasks in them are usually not bound by any school or national curriculum and they can freely explore any concepts they found interesting and worthwhile. But many of these concept are not used in high school education and they appear exclusively at universities. We believe that this is not due to their complexity, but because they are lacking simple and intuitive way of presentation. So it should be interesting to look, if we can use experiences obtained in informatics competitions and translate them to high school classes.

In this paper, we focused on Slovak informatics competition PRASK. It is an algorithmic competition for talented middle schoolers (approx. ages 11-15), where contestants solve many algorithmic tasks, often devising complex algorithms with the help of slowly graduated subtasks. As a main concept of this paper, we chose binary search trees (BST). Idea behind this structure is elegant and intuitive and so it was a perfect fit for this competition.

We developed a set of tasks in which pupils are presented with structure of BST and they need to figure out on their own basic functionality - search, insert and delete. This tasks were used in PRASK competition, which was held during october 2017. After the end of the competition we analyzed contestants’ solutions and modify it into a 45 minute long activity, which could be used as a single lesson, similar to CSUnplugged activities [2]. We then tested this activity with four groups of high schoolers during they computer science classes and one group of high schoolers, which consisted of participants of summer programming school we organized.

In this paper, we summarize our preliminary results. We will talk about development of the task, results of first analysis, modification we did during transition to an activity and we will show analysis of pupils’ solutions. In the end, we will summarize our findings, discuss benefits of using this type of tasks, and outline possible continuation.

References:
[1] Jeannette M Wing. Computational thinking. Communications of the ACM, 49(3):33–35, 2006.
[2] https://csunplugged.org/en/.

Keywords:

Binary search trees, competition, high school, informatics.