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| 1 | +package com.macasaet; |
| 2 | + |
| 3 | +import org.junit.jupiter.api.Test; |
| 4 | + |
| 5 | +import java.util.stream.Stream; |
| 6 | +import java.util.stream.StreamSupport; |
| 7 | + |
| 8 | +/** |
| 9 | + * --- Day 4: Camp Cleanup --- |
| 10 | + * <a href="https://adventofcode.com/2022/day/4">https://adventofcode.com/2022/day/4</a> |
| 11 | + */ |
| 12 | +public class Day04 { |
| 13 | + |
| 14 | + /** |
| 15 | + * One crew member responsible for cleaning up the camp. They are responsible for a contiguous range of sections. |
| 16 | + * |
| 17 | + * @param sectionMin the lowest section ID for which this Elf is responsible (inclusive) |
| 18 | + * @param sectionMax the highest section ID for which this Elf is responsible (inclusive). |
| 19 | + */ |
| 20 | + public record Elf(int sectionMin, int sectionMax) { |
| 21 | + |
| 22 | + public boolean fullyContains(final Elf other) { |
| 23 | + return sectionMin() <= other.sectionMin() && sectionMax() >= other.sectionMax(); |
| 24 | + } |
| 25 | + |
| 26 | + public static Elf parse(final String string) { |
| 27 | + final var components = string.split("-"); |
| 28 | + return new Elf(Integer.parseInt(components[0]), Integer.parseInt(components[1])); |
| 29 | + } |
| 30 | + } |
| 31 | + |
| 32 | + /** |
| 33 | + * Two elves (of a larger crew) assigned to clean up the camp. |
| 34 | + */ |
| 35 | + public record Pair(Elf left, Elf right) { |
| 36 | + public boolean oneFullyContainsTheOther() { |
| 37 | + return left.fullyContains(right) || right.fullyContains(left); |
| 38 | + } |
| 39 | + public boolean hasOverlap() { |
| 40 | + return (left.sectionMin() <= right.sectionMin() && left.sectionMax() >= right.sectionMin()) |
| 41 | + || (right.sectionMin() <= left.sectionMin() && right.sectionMax() >= left.sectionMin()); |
| 42 | + } |
| 43 | + public static Pair parse(final String line) { |
| 44 | + final var components = line.split(","); |
| 45 | + return new Pair(Elf.parse(components[0]), Elf.parse(components[1])); |
| 46 | + } |
| 47 | + } |
| 48 | + protected Stream<Pair> getInput() { |
| 49 | + return StreamSupport |
| 50 | + .stream(new LineSpliterator("day-04.txt"), |
| 51 | + false) |
| 52 | + .map(Pair::parse); |
| 53 | + } |
| 54 | + |
| 55 | + @Test |
| 56 | + public final void part1() { |
| 57 | + final var result = getInput().filter(Pair::oneFullyContainsTheOther).count(); |
| 58 | + |
| 59 | + System.out.println("Part 1: " + result); |
| 60 | + } |
| 61 | + |
| 62 | + @Test |
| 63 | + public final void part2() { |
| 64 | + final var result = getInput().filter(Pair::hasOverlap).count(); |
| 65 | + |
| 66 | + System.out.println("Part 2: " + result); |
| 67 | + } |
| 68 | + |
| 69 | +} |
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