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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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35
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
// 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
//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
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{
//The largest number to be checked
public static final Integer MAX_NUM = 28123;
public static final int MAX_NUM = 28123;
public Problem23(){
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
timer.start();
//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);
//Remove the last element, which is the number itself. This gives us the propper divisors
if(div.size() > 1){
@@ -59,17 +60,17 @@ public class Problem23 extends Problem{
//Get the abundant numbers
ArrayList<Integer> abund = new ArrayList<Integer>();
for(Integer cnt = 0;cnt.compareTo(divisorSums.size()) < 0;++cnt){
if(divisorSums.get(cnt) > cnt.longValue()){
for(int cnt = 0;cnt < divisorSums.size();++cnt){
if(divisorSums.get(cnt) > cnt){
abund.add(cnt);
}
}
//Check if each number can be the sum of 2 abundant numbers and add to the sum if no
Long sum = 0L;
for(Integer cnt = 1;cnt.compareTo(MAX_NUM) < 0;++cnt){
long sum = 0L;
for(int cnt = 1;cnt < MAX_NUM;++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);
}
//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){
Integer sum = 0;
private boolean isSum(final ArrayList<Integer> abund, int num){
int sum = 0;
//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
for(Integer secondNum = firstNum;secondNum < abund.size();++secondNum){
for(int secondNum = firstNum;secondNum < abund.size();++secondNum){
sum = abund.get(firstNum) + abund.get(secondNum);
if(sum.equals(num)){
if(sum == num){
return true;
}
else if(sum.compareTo(num) > 0){
else if(sum > num){
break;
}
}
@@ -102,5 +103,5 @@ public class Problem23 extends Problem{
/* Results:
The answer is 4179871
It took 49.791 seconds to solve this problem.
It took 12.277 seconds to solve this problem.
*/