notebook.py

            print("No algorithm to run.")
            return 0
        
        def slider_callback(iteration):
            # don't show graph for the first time running the cell calling this function
            try:
                show_map(graph_data, node_colors=all_node_colors[iteration])
            except:
                pass
            
        def visualize_callback(Visualize):
            if Visualize is True:
                button.value = False
                
                problem = GraphProblem(start_dropdown.value, end_dropdown.value, romania_map)
                global all_node_colors
                
                user_algorithm = algorithm[algo_dropdown.value]
                
                iterations, all_node_colors, node = user_algorithm(problem)
                solution = node.solution()
                all_node_colors.append(final_path_colors(all_node_colors[0], problem, solution))

                slider.max = len(all_node_colors) - 1
                
                for i in range(slider.max + 1):
                    slider.value = i
                    #time.sleep(.5)
                         
        start_dropdown = widgets.Dropdown(description="Start city: ",
                                          options=sorted(list(node_colors.keys())), value="Arad")
        display(start_dropdown)

        end_dropdown = widgets.Dropdown(description="Goal city: ",
                                        options=sorted(list(node_colors.keys())), value="Fagaras")
        display(end_dropdown)
        
        button = widgets.ToggleButton(value=False)
        button_visual = widgets.interactive(visualize_callback, Visualize=button)
        display(button_visual)
        
        slider = widgets.IntSlider(min=0, max=1, step=1, value=0)
        slider_visual = widgets.interactive(slider_callback, iteration=slider)
        display(slider_visual)