An algorithm like Ternary Search can be understood easily by visualizing. In this article, a program that visualizes the Ternary Search Algorithm has been implemented. The Graphical User Interface(GUI) is implemented in Python using pygame library.
Approach
Generate random array, sort it using any sorting algorithm, and fill the pygame window with bars. Bars are straight vertical lines, which represent array elements.
- Set all bars to green color.
- Use pygame.time.delay() to slow down the algorithm, so that we can see the searching process.
- Implement a timer to see how the algorithm performs.
- The actions are performed using ‘pygame.event.get()’ method, which stores all the events which the user performs, such as start, reset.
- The blue color is used to highlight the bar equal to the key if found.
- Red color highlights the left and right bars.
- Orange color highlights the mid1 and mid2 bars.
Below is the implementation of the above visualizer.
Python
# Python implementation of the # Sorting visualiser: Insertion Sort   import pygame import random import time     pygame.font.init() startTime = time.time()   # Total window screen = pygame.display.set_mode(     (900, 650) )   # Title and Icon pygame.display.set_caption(     "TERNARY SEARCH VISUALISER")   # Uncomment below lines for setting # up the icon for the visuliser # img = pygame.image.load('sorticon.png') # pygame.display.set_icon(img)   # Boolean variable to run # the program in while loop run = True  # Window size and some initials width = 900length = 600array = [0]*151key = 0foundkey = Falsearr_clr = [(0, 204, 102)]*151clr_ind = 0clr = [(0, 204, 102), (255, 0, 0),        (0, 0, 153), (255, 102, 0)] bigfont = pygame.font.SysFont("comicsans", 70) fnt = pygame.font.SysFont("comicsans", 30) fnt1 = pygame.font.SysFont("comicsans", 20)   # Sorting Algorithm: Heap Sort def heapSort(array):         n = len(array)           for i in range(n//2-1, -1, -1):         heapify(array, i, n)           for i in range(n-1, 0, -1):         array[i], array[0] = array[0], array[i]         heapify(array, 0, i)     def heapify(array, root, size):           left = root*2+1    right = root*2+2    largest = root           if left < size and array[left] > array[largest]:         largest = left           if right < size and array[right] > array[largest]:         largest = right           if largest != root:         array[largest], array[root] = array[root], array[largest]         heapify(array, largest, size)   # Function to generate new Array def generate_arr():           for i in range(1, 151):         arr_clr[i] = clr[0]         array[i] = random.randrange(1, 100)     heapSort(array)     # Initially generate a array generate_arr()   # Function to refill the # updates on the window def refill():           screen.fill((255, 255, 255))     draw()     pygame.display.update()     pygame.time.delay(200)     def ternarySearch(array, key):     left = 1    right = len(array)-1      while left <= right:         pygame.event.pump()         arr_clr[left] = clr[1]         arr_clr[right] = clr[1]         mid1 = left+(right-left)//3        mid2 = right-(right-left)//3        arr_clr[mid1] = clr[3]         arr_clr[mid2] = clr[3]         refill()         pygame.event.pump()         refill()         refill()         arr_clr[left] = clr[0]         arr_clr[right] = clr[0]         arr_clr[mid1] = clr[0]         arr_clr[mid2] = clr[0]                   if key == array[mid1]:             arr_clr[mid1] = clr[2]             return 1                  if key == array[mid2]:             arr_clr[mid1] = clr[2]             return 1          if key < array[mid1]:             right = mid1-1        elif key > array[mid2]:             left = mid2+1        else:             left = mid1+1            right = mid2-1        refill()       return -1    # Function to Draw the array values def draw():         # Text should be rendered     txt = fnt.render("SEARCH: PRESS 'ENTER'",                      1, (0, 0, 0))           # Position where text is placed     screen.blit(txt, (20, 20))     txt1 = fnt.render("NEW ARRAY: PRESS 'R'",                       1, (0, 0, 0))     screen.blit(txt1, (20, 40))       txt2 = fnt1.render("ENTER NUMBER TO SEARCH:" +                       str(key), 1, (0, 0, 0))     screen.blit(txt2, (600, 60))       text3 = fnt1.render("Running Time(sec): " +                        str(int(time.time() - startTime)),                         1, (0, 0, 0))     screen.blit(text3, (600, 20))       element_width = (width-150)//150    boundry_arr = 900 / 150    boundry_grp = 550 / 100    pygame.draw.line(screen, (0, 0, 0), (0, 95),                      (900, 95), 6)       # Drawing the array values as lines     for i in range(1, 151):         pygame.draw.line(screen, arr_clr[i],                          (boundry_arr * i-3, 100),                          (boundry_arr * i-3,                           array[i]*boundry_grp + 100), element_width)     if foundkey == 1:         text4 = bigfont.render("Key Found. Press N to Reset Key", 1, (0, 0, 0))         screen.blit(text4, (100, 300))       elif foundkey == -1:         text4 = bigfont.render(             "Key Not Found. Press N to Reset Key", 1, (0, 0, 0))         screen.blit(text4, (30, 300))     # Program should be run # continuously to keep the window open while run:         # background     screen.fill((255, 255, 255))       # Event handler stores all event     for event in pygame.event.get():           # If we click Close button in window         if event.type == pygame.QUIT:             run = False        if event.type == pygame.KEYDOWN:                           if event.key == pygame.K_r:                 key = 0                foundkey = 0                generate_arr()                           if event.key == pygame.K_n:                 foundkey = 0                key = 0                for i in range(0, len(array)):                     arr_clr[i] = clr[0]               if event.key == pygame.K_RETURN and key != 0:                 foundkey = ternarySearch(array, key)                 print("hello")               if event.key == pygame.K_0:                 key = key*10              if event.key == pygame.K_1:                 key = key*10+1              if event.key == pygame.K_2:                 key = key*10+2              if event.key == pygame.K_3:                 key = key*10+3              if event.key == pygame.K_4:                 key = key*10+4              if event.key == pygame.K_5:                 key = key*10+5              if event.key == pygame.K_6:                 key = key*10+6              if event.key == pygame.K_7:                 key = key*10+7              if event.key == pygame.K_8:                 key = key*10+8              if event.key == pygame.K_9:                 key = key*10+9      draw()     pygame.display.update()   pygame.quit() |
Output:
