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Exponential Search Visualizer using PyQt5

  • Last Updated : 06 May, 2020

In this article we will see how we can make a PyQt5 application which will visualize the Exponential search algorithm.

Exponential search can also be used to search in bounded lists. Exponential search can even out-perform more traditional searches for bounded lists, such as binary search, when the element being searched for is near the beginning of the array. This is because exponential search will run in O(log i) time, where i is the index of the element being searched for in the list, whereas binary search would run in O(log n) time, where n is the number of elements in the list.

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GUI implementation steps :

1. Create a list of label according to the given list of numbers
2. Set their text, border, color and geometry with the respective gap from each other
3. Each label height should be proportional to the value of each number
4. Create a start and pause push button to start the searching and pause the searching
5. Create a result label to show the searching status

Back end implementation steps :
1. Create label list corresponding to the given numbers
2. Create variable for the index used by exponential search and other variable used by binary search index and flag for searching and flag for binary and exponential search.
3. Add action to the push button their action should change the flag status i.e start action should make flag true and pause action should make flag false.
4. Create timer object which calls a method after every specific time
5. Inside the timer method check for the flag is flag is true begin the exponential search algorithm
6. Check if value lies within the range if not show output as not found else continue
7. Start finding value at index if found stop the search and show result else double the index value
8. Find the range in which value would be and start binary search and set the lower and upper value of binary search
9. Show result with the help of binary search

Below is the implementation




# importing libraries
from PyQt5.QtWidgets import * 
from PyQt5 import QtCore, QtGui
from PyQt5.QtGui import * 
from PyQt5.QtCore import * 
import sys
  
  
class Window(QMainWindow):
    # list of numbers
    number = [1, 2, 3, 4, 5, 6, 7, 8, 9,
                 10, 11, 12, 13, 14, 15]
  
    def __init__(self):
        super().__init__()
  
        # setting title
        self.setWindowTitle("Exponential Search")
  
        # setting geometry
        self.setGeometry(100, 100, 600, 400)
  
        # calling method
        self.UiComponents()
  
        # showing all the widgets
        self.show()
  
    # method for widgets
    def UiComponents(self):
  
        # start flag
        self.start = False
        self.binary = False
        self.expo = True
  
        # list to hold labels
        self.label_list = []
  
        # desired value
        self.desired = 8
  
        # Exponential Search variable
        self.index = 1
  
        # binary search variable
        self.first = 0
        self.last = len(self.number) - 1
        self.mid = 0
  
        # local counter
        c = 0
  
        # iterating list of numbers
        for i in self.number:
            # creating label for each number
            label = QLabel(str(i), self)
  
            # adding background color and border
            label.setStyleSheet("border : 1px solid black; 
                                 background : white;")
  
            # aligning the text
            label.setAlignment(Qt.AlignTop)
  
            # setting geometry using local counter
            # first parameter is distance from left
            # and second is distance from top
            # third is width and forth is height
            label.setGeometry(50 + c * 30, 50, 20, i * 10 + 10)
  
            # adding label to the label list
            self.label_list.append(label)
  
            # incrementing local counter
            c = c + 1
  
        # creating push button to start the search
        self.search_button = QPushButton("Start Search", self)
  
        # setting geometry of the button
        self.search_button.setGeometry(100, 270, 100, 30)
  
        # adding action to the search button
        self.search_button.clicked.connect(self.search_action)
  
        # creating push button to pause the search
        pause_button = QPushButton("Pause", self)
  
        # setting geometry of the button
        pause_button.setGeometry(100, 320, 100, 30)
  
        # adding action to the search button
        pause_button.clicked.connect(self.pause_action)
  
        # creating label to show the result
        self.result = QLabel("To search : " + str(self.desired), self)
  
        # setting geometry
        self.result.setGeometry(350, 280, 200, 40)
  
        # setting style sheet
        self.result.setStyleSheet("border : 3px solid black;")
  
        # adding font
        self.result.setFont(QFont('Times', 10))
  
        # setting alignment
        self.result.setAlignment(Qt.AlignCenter)
  
        # creating a timer object
        timer = QTimer(self)
  
        # adding action to timer
        timer.timeout.connect(self.showTime)
  
        # update the timer every 300 millisecond
        timer.start(300)
  
    # method called by timer
    def showTime(self):
  
        # checking if flag is true
        if self.start:
  
            # Exponential Search
            if self.expo:
  
                # if equal for index value 0
                if self.number[0] == self.desired:
                    # stop the searching
                    self.start = False
  
                    # show the result and make the label green
                    self.result.setText("Found at index : 0" )
                    self.label_list[self.index].setStyleSheet(
                                    "border : 2px solid green;"
                                    "background-color : lightgreen")
  
                # if not equal
                else:
                    # make the label grey
                    self.label_list[0].setStyleSheet(
                              "border : 1px solid black;"
                              "background-color : grey")
  
  
                # double the value of index
                self.index = self.index * 2
  
                # temporary stores index
                temp = self.index
  
                # checking if index is greater then the len of list
                if self.index >= len(self.number):
  
                    # update the index
                    self.index = len(self.number) - 1
  
                    # start binary search
                    self.expo = False
                    self.binary = True
  
                    # set variable of binary search
                    self.first = temp//2
                    self.last = self.index
  
                # if desired value is smaller
                if self.desired < self.number[self.index]:
  
                    # start binary search
                    self.expo = False
                    self.binary = True
  
                    # set binary search variables
                    self.first = temp//2
                    self.last = self.index
  
                # if number is equal to the index value
                if self.number[self.index] == self.desired:
  
                    # stop the search
                    self.start = False
  
                    # show result and make label color green
                    self.result.setText("Found at index : " + str(self.index))
                    self.label_list[self.index].setStyleSheet(
                                    "border : 2px solid green;"
                                    "background-color : lightgreen")
  
                # if not equal
                else:
                    # make label color grey
                    self.label_list[self.index].setStyleSheet(
                                    "border : 1px solid black;"
                                    "background-color : grey")
  
  
            # binary search
            if self.binary:
                # implementing binary search
                # finding mid index
                self.mid = (self.first + self.last) // 2
  
                # if first index become greater than last index
                if self.first > self.last:
                    # make start flag false
                    self.start = False
                    # show output as not found
                    self.result.setText("Not Found")
  
                # if mid value is equal to the desired value
                if self.number[self.mid] == self.desired:
  
                    # make flag false
                    self.start = False
  
                    # show output in result label
                    self.result.setText("Found at index : " + str(self.mid))
  
                    # set color of label to green
                    self.label_list[self.mid].setStyleSheet(
                                     "border : 2px solid green; "
                                     "background-color : lightgreen")
  
                # if not equal to mid value
                else:
                    # make color grey
                    self.label_list[self.mid].setStyleSheet(
                                  "border : 1px solid black; "
                                  "background-color : grey")
  
                # mid value is higher
                if self.number[self.mid] > self.desired:
                    # change last index
                    self.last = self.mid - 1
  
                # if mid value is smaller
                if self.number[self.mid] < self.desired:
                    # change first index
                    self.first = self.mid + 1
  
    # method called by search button
    def search_action(self):
  
        # making flag true
        self.start = True
  
        # showing text in result label
        self.result.setText("Started searching...")
  
    # method called by pause button
    def pause_action(self):
  
        # making flag false
        self.start = False
  
        # showing text in result label
        self.result.setText("Paused")
  
  
# create pyqt5 app
App = QApplication(sys.argv)
  
# create the instance of our Window
window = Window()
  
# start the app
sys.exit(App.exec())

Output :




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