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ProjectEulerPython/Problem4.py

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Python

#ProjectEuler/Python/Problem4.py
#Matthew Ellison
# Created: 01-28-19
#Modified: 03-28-19
#Find the largest palindrome made from the product of two 3-digit numbers
#Unless otherwise listed, all of my non-standard imports can be gotten from my pyClasses repository at https://bitbucket.org/Mattrixwv/pyClasses
"""
Copyright (C) 2019 Matthew Ellison
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
"""
from Stopwatch import Stopwatch
__lowestNum = 100
__highestNum = 1000
def Problem4():
#Setup the variables
palindromes = [] #Holds all of the palindromes
currentNum = 0 #Holds the product of the two numbers I am currently working on
#Loop through every number from __lowestNum to __highestNum twice and multiply every number together
for num1 in range(__lowestNum, __highestNum + 1):
for num2 in range(num1, __highestNum + 1): #You can start at num1 because 100 * 101 == 101 * 100
currentNum = num1 * num2
#If the number is a palindrome add it to the list of palindromes, otherwise ignore it
#Using strings makes it easier to determine a palindrome
if(str(currentNum) == str(currentNum)[::-1]):
palindromes.append(currentNum)
#Sort the palindromes so that the last element is the largest
palindromes.sort()
#Print the results
print("The largest palindrome made from the product of two 3-digit numbers is " + str(palindromes[len(palindromes) - 1]))
#If you are running this file, automatically start the correct function
if __name__ == '__main__':
timer = Stopwatch() #Determines the algorithm's run time
timer.start() #Start the timer
Problem4() #Call the function that answers the question
timer.stop() #Stop the timer
#Print the results of the timer
print("It took " + timer.getString() + " to run this algorithm")
"""Results:
The largest palindrome made from the product of two 3-digit numbers is 906609
It took 177.314 milliseconds to run this algorithm
"""