#ProjectEuler/Python/Problem23.py #Matthew Ellison # Created: 03-22-19 #Modified: 07-24-21 #Find the sum of all the positive integers which cannot be written as the sum of two abundant numbers #All of my imports can be gotten from my pyClasses repository at https://bitbucket.org/Mattrixwv/pyClasses """ Copyright (C) 2021 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 . """ from Problems.Problem import Problem import NumberAlgorithms class Problem23(Problem): #Variables __maxNum = 28123 #Functions #Constructor def __init__(self) -> None: super().__init__("Find the sum of all the positive integers which cannot be written as the sum of two abundant numbers") self.divisorSums = [] self.reserveArray() self.sum = 0 #Operational functions #Solve the problem def solve(self) -> None: #If the problem has already been solved do nothing and end the function if(self.solved): return #Start the timer self.timer.start() #Get the sum of the divisors of all numbers < __maxNum for cnt in range(1, self.__maxNum): div = NumberAlgorithms.getDivisors(cnt) if(len(div) > 1): div.remove(div[len(div) - 1]) self.divisorSums[cnt] = sum(div) #Get the abundant numbers abund = [] for cnt in range(0, len(self.divisorSums)): if(self.divisorSums[cnt] > cnt): abund.append(cnt) #Check if each number can be the sum of 2 abundant numbers and add to the sum if no self.sum = 0 for cnt in range(1, self.__maxNum): if(not self.isSum(abund, cnt)): self.sum += cnt #Stop the timer self.timer.stop() #Throw a flag to show the problem is solved self.solved = True #Reserve the size of the array to speed up insertion def reserveArray(self) -> None: #Make sure every element has a 0 in it's location for _ in range(0, self.__maxNum): self.divisorSums.append(0) #A function that returns true if num can be created by adding two elements from abund and false if it cannot def isSum(self, abund: list, num: int) -> bool: sumOfNums = 0 #Pick a number for the first part of the sum for firstNum in range(0, len(abund)): #Pick a number for the second part of the sum for secondNum in range(0, len(abund)): sumOfNums = abund[firstNum] + abund[secondNum] if(sumOfNums == num): return True elif(sumOfNums > num): break #If you have run through the entire list and did not find a sum then it is false return False #Reset the problem so it can be run again def reset(self) -> None: super().reset() self.divisorSums.clear() self.reserveArray() self.sum = 0 #Gets #Returns the result of solving the problem def getResult(self) -> str: self.solvedCheck("result") return f"The answer is {self.sum}" #Returns the sum of the numbers asked for def getSum(self) -> int: self.solvedCheck("sum") return self.sum """ Results: The answer is 4179871 It took an average of 24.184 minutes to run this problem through 10 iterations """