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Commit 5a4a69d

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Solved Day 20 (2015) - Infinite Elves and Infinite Houses
1 parent f489a18 commit 5a4a69d

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  • src/main/java/com/sbaars/adventofcode/year15/days

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package com.sbaars.adventofcode.year15.days;
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import com.sbaars.adventofcode.year15.Day2015;
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import java.util.*;
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import java.util.stream.IntStream;
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public class Day20 extends Day2015 {
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public Day20() {
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super(20);
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}
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public static void main(String[] args) {
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new Day20().printParts();
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}
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@Override
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public Object part1() {
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return "";
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}
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@Override
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public Object part2() {
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return "";
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}
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private static final int TARGET_PRESENTS = 36000000;
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private static final int PRESENTS_PER_ELF = 10;
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public Day20() {
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super(20);
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}
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public static void main(String[] args) {
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Day20 day = new Day20();
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day.printParts();
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new com.sbaars.adventofcode.network.Submit().submit(day.part1(), 2015, 20, 1);
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}
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@Override
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public Object part1() {
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int houseNumber = 1;
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while (getPresentsForHouse(houseNumber) < TARGET_PRESENTS) {
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houseNumber++;
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}
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return houseNumber;
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}
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@Override
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public Object part2() {
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return 0; // Implement in next part
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}
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private int getPresentsForHouse(int houseNumber) {
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return getDivisors(houseNumber).stream()
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.mapToInt(divisor -> divisor * PRESENTS_PER_ELF)
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.sum();
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}
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private Set<Integer> getDivisors(int number) {
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Set<Integer> divisors = new HashSet<>();
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int sqrt = (int) Math.sqrt(number);
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for (int i = 1; i <= sqrt; i++) {
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if (number % i == 0) {
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divisors.add(i);
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divisors.add(number / i);
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}
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}
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return divisors;
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}
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}

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