Willow: A Tool for Interactive Programming Visualization to Help in the Data Structures and Algorithms Teaching-Learning Process

Data Structures and Algorithms (DSA) are one of the main pillars of software development; however, abstractions around them are hard to teach and to be understood by students. The most common approaches adopted by instructors to demonstrate the behavior of DSAs are the use of resources like slides and whiteboard sketches to create program illustrations. This task may be slow and tedious because these illustrations need to be continuously updated to represent new algorithm inputs and modifications. In this paper, we propose Willow, a tool for Program Visualization Simulation (PVS), which supports user interactions to manipulate the generated visualizations. With these manipulations in the visualization, we expect the user to be able to create better examples, resembling Algorithm Visualization Simulation tools (AVS), which are specialized in providing visualizations for specific DSAs. We evaluated our tool through a preliminary qualitative study with teaching assistants from an introductory Computer Science course who all give review lessons to the students. Our preliminary results show that the tool was well accepted by the participants, but we still need more studies to validate the use of the tool in classrooms. With the use of our tool features in the teaching-learning process, we expect that instructors may be able to interactively and more clearly explain DSAs to their students, without the hassle of hours creating slides or drawing by hand messy examples of algorithms.