Day 4

l0s · l0s · commit 21710bbe5a42 · 2022-12-03T21:17:43.000-08:00
diff --git a/src/test/java/com/macasaet/Day04.java b/src/test/java/com/macasaet/Day04.java
@@ -0,0 +1,69 @@
+package com.macasaet;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+/**
+ * --- Day 4: Camp Cleanup ---
+ * <a href="https://adventofcode.com/2022/day/4">https://adventofcode.com/2022/day/4</a>
+ */
+public class Day04 {
+
+    /**
+     * One crew member responsible for cleaning up the camp. They are responsible for a contiguous range of sections.
+     *
+     * @param sectionMin the lowest section ID for which this Elf is responsible (inclusive)
+     * @param sectionMax the highest section ID for which this Elf is responsible (inclusive).
+     */
+    public record Elf(int sectionMin, int sectionMax) {
+
+        public boolean fullyContains(final Elf other) {
+            return sectionMin() <= other.sectionMin() && sectionMax() >= other.sectionMax();
+        }
+
+        public static Elf parse(final String string) {
+            final var components = string.split("-");
+            return new Elf(Integer.parseInt(components[0]), Integer.parseInt(components[1]));
+        }
+    }
+
+    /**
+     * Two elves (of a larger crew) assigned to clean up the camp.
+     */
+    public record Pair(Elf left, Elf right) {
+        public boolean oneFullyContainsTheOther() {
+            return left.fullyContains(right) || right.fullyContains(left);
+        }
+        public boolean hasOverlap() {
+            return (left.sectionMin() <= right.sectionMin() && left.sectionMax() >= right.sectionMin())
+                    || (right.sectionMin() <= left.sectionMin() && right.sectionMax() >= left.sectionMin());
+        }
+        public static Pair parse(final String line) {
+            final var components = line.split(",");
+            return new Pair(Elf.parse(components[0]), Elf.parse(components[1]));
+        }
+    }
+    protected Stream<Pair> getInput() {
+        return StreamSupport
+                .stream(new LineSpliterator("day-04.txt"),
+                        false)
+                .map(Pair::parse);
+    }
+
+    @Test
+    public final void part1() {
+        final var result = getInput().filter(Pair::oneFullyContainsTheOther).count();
+
+        System.out.println("Part 1: " + result);
+    }
+
+    @Test
+    public final void part2() {
+        final var result = getInput().filter(Pair::hasOverlap).count();
+
+        System.out.println("Part 2: " + result);
+    }
+
+}
diff --git a/src/test/resources/sample/day-04.txt b/src/test/resources/sample/day-04.txt
@@ -0,0 +1,6 @@
+2-4,6-8
+2-3,4-5
+5-7,7-9
+2-8,3-7
+6-6,4-6
+2-6,4-8

-Original file line number
+Diff line change
@@ @@ -0,0 +1,6 @@ @@
 +2-4,6-8
 +2-3,4-5
 +5-7,7-9
 +2-8,3-7
 +6-6,4-6
 +2-6,4-8