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Updated for performance

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Mattrixwv
2020-06-17 14:54:08 -04:00
parent fc4d6c7e69
commit e18591046e
1 changed files with 18 additions and 17 deletions
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src/main/java/mattrixwv/ProjectEuler/Problems/Problem23.java
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@@ -1,11 +1,11 @@
//ProjectEuler/C++/Problem23.java //ProjectEulerJava/src/main/java/mattrixwv/ProjectEuler/Problems/Problem23.java
//Matthew Ellison //Matthew Ellison
// Created: 03-22-19 // Created: 03-22-19
//Modified: 03-28-19 //Modified: 06-17-20
//Find the sum of all the positive integers which cannot be written as the sum of two abundant numbers //Find the sum of all the positive integers which cannot be written as the sum of two abundant numbers
//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/JavaClasses //Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/JavaClasses
/* /*
Copyright (C) 2019 Matthew Ellison Copyright (C) 2020 Matthew Ellison
This program is free software: you can redistribute it and/or modify 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 it under the terms of the GNU Lesser General Public License as published by
@@ -30,7 +30,7 @@ import java.util.ArrayList;
public class Problem23 extends Problem{ public class Problem23 extends Problem{
//The largest number to be checked //The largest number to be checked
public static final Integer MAX_NUM = 28123; public static final int MAX_NUM = 28123;
public Problem23(){ public Problem23(){
super("Find the sum of all the positive integers which cannot be written as the sum of two abundant numbers"); super("Find the sum of all the positive integers which cannot be written as the sum of two abundant numbers");
@@ -47,8 +47,9 @@ public class Problem23 extends Problem{
//Start the timer //Start the timer
timer.start(); timer.start();
//Get the sum of the divisors of all numbers < MAX_NUM //Get the sum of the divisors of all numbers < MAX_NUM
for(Integer cnt = 1;cnt.compareTo(MAX_NUM) < 0;++cnt){ for(int cnt = 1;cnt < MAX_NUM;++cnt){
ArrayList<Integer> div = Algorithms.getDivisors(cnt); ArrayList<Integer> div = Algorithms.getDivisors(cnt);
//Remove the last element, which is the number itself. This gives us the propper divisors //Remove the last element, which is the number itself. This gives us the propper divisors
if(div.size() > 1){ if(div.size() > 1){
@@ -59,17 +60,17 @@ public class Problem23 extends Problem{
//Get the abundant numbers //Get the abundant numbers
ArrayList<Integer> abund = new ArrayList<Integer>(); ArrayList<Integer> abund = new ArrayList<Integer>();
for(Integer cnt = 0;cnt.compareTo(divisorSums.size()) < 0;++cnt){ for(int cnt = 0;cnt < divisorSums.size();++cnt){
if(divisorSums.get(cnt) > cnt.longValue()){ if(divisorSums.get(cnt) > cnt){
abund.add(cnt); abund.add(cnt);
} }
} }
//Check if each number can be the sum of 2 abundant numbers and add to the sum if no //Check if each number can be the sum of 2 abundant numbers and add to the sum if no
Long sum = 0L; long sum = 0L;
for(Integer cnt = 1;cnt.compareTo(MAX_NUM) < 0;++cnt){ for(int cnt = 1;cnt < MAX_NUM;++cnt){
if(!isSum(abund, cnt)){ if(!isSum(abund, cnt)){
sum += cnt.longValue(); sum += cnt;
} }
} }
@@ -80,17 +81,17 @@ public class Problem23 extends Problem{
result = String.format("The answer is %d\n", sum); result = String.format("The answer is %d\n", sum);
} }
//A function that returns true if num can be created by adding two elements from abund and false if it cannot //A function that returns true if num can be created by adding two elements from abund and false if it cannot
private Boolean isSum(final ArrayList<Integer> abund, Integer num){ private boolean isSum(final ArrayList<Integer> abund, int num){
Integer sum = 0; int sum = 0;
//Pick a number for the first part of the sum //Pick a number for the first part of the sum
for(Integer firstNum = 0;firstNum < abund.size();++firstNum){ for(int firstNum = 0;firstNum < abund.size();++firstNum){
//Pick a number for the second part of the sum //Pick a number for the second part of the sum
for(Integer secondNum = firstNum;secondNum < abund.size();++secondNum){ for(int secondNum = firstNum;secondNum < abund.size();++secondNum){
sum = abund.get(firstNum) + abund.get(secondNum); sum = abund.get(firstNum) + abund.get(secondNum);
if(sum.equals(num)){ if(sum == num){
return true; return true;
} }
else if(sum.compareTo(num) > 0){ else if(sum > num){
break; break;
} }
} }
@@ -102,5 +103,5 @@ public class Problem23 extends Problem{
/* Results: /* Results:
The answer is 4179871 The answer is 4179871
It took 49.791 seconds to solve this problem. It took 12.277 seconds to solve this problem.
*/ */