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:
