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 = 900
length = 600
array = [ 0 ] * 151
key = 0
foundkey = False
arr_clr = [( 0 , 204 , 102 )] * 151
clr_ind = 0
clr = [( 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:
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