In this article we will see how we can make a PyQt5 application which will visualize the subset search algorithm.
Sub Set Search : Sometimes we encounter the problem of checking if one list is just an extension of the list i.e just a superset of one list. This kind of problems are quite popular in competitive programming.
Examples –
Input: list = [1, 2, 3, 4, 5, 6, 7], sub-list = [2, 4, 7]
Output : List FoundInput: list = [1, 2, 3, 4, 5, 6, 7], sub-list = [5, 1, 7]
Output : List Found
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 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 statusBack end implementation steps :
1. Create label list corresponding to the given numbers
2. Create variable for the list index and sub-list index and flag for searching
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 and a counter to count number of matches
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 perfect sub-list search algorithm
6. Check for the first element of sub-list with first element of the list if found increment sub-list index, increment counter and reset the index of list else increment list index
7. If the index becomes equal to the list length stop the search and show result as not found.
8. If counter becomes equal to the length of the sub-list show result as found.
Below is the implementation
Python3
# importing librariesfrom PyQt5.QtWidgets import *from PyQt5 import QtCore, QtGuifrom PyQt5.QtGui import *from PyQt5.QtCore import *import sysclass Window(QMainWindow): # list of numbers number = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15] # desired list desired = [10, 11, 8, 4] def __init__(self): super().__init__() # setting title self.setWindowTitle("Sub Set 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 # list to hold labels self.label_list = [] # match sub list self.match = [] # index of both list self.list_index = 0 self.sub_index = 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(320, 280, 250, 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: # if index exceeds limit if self.list_index >= len(self.number): # stop the search and show result not found self.start = False self.result.setText("Not Found") return # check for the element if self.desired[self.sub_index] == self.number[self.list_index]: # append it the match counter self.match.append(self.list_index) # make label color yellow and rest of whitee color for i in range(len(self.label_list)): self.label_list[i].setStyleSheet( "border : 1px solid yellow;" "background-color : white;" ) # for matched label make them yellow color if i in self.match: self.label_list[i].setStyleSheet( "border : 2px solid yellow;" "background-color : yellow;" ) # increment sub index self.sub_index += 1 # reset the list index self.list_index = 0 # if not found else: # make checked index label grey self.label_list[self.sub_index + self.list_index].setStyleSheet( "border :" "1px solid black;" "background-color : grey;" ) # increment list index self.list_index += 1 # if matches become equal to desired list if len(self.match) == len(self.desired): # stop search self.start =False # show result self.result.setText("Found at : " + str(self.match)) # make matched index green for i in self.match: self.label_list[i].setStyleSheet( "border : 2px solid green;" "background-color : lightgreen;") # 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 appApp = QApplication(sys.argv)# create the instance of our Windowwindow = Window()# start the appsys.exit(App.exec()) |
Output :
