使用 PyQt5 的指数搜索可视化工具
在本文中，我们将看到如何制作一个 PyQt5 应用程序，它将可视化指数搜索算法。
指数搜索也可用于在有界列表中进行搜索。当要搜索的元素靠近数组的开头时，指数搜索甚至可以胜过更传统的有界列表搜索，例如二进制搜索。这是因为指数搜索将在 O(log i) 时间内运行，其中 i 是要在列表中搜索的元素的索引，而二进制搜索将在 O(log n) 时间内运行，其中 n 是元素的数量在列表中。
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
下面是实现
# 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())
输出 ：