2015 Day 16

Author: dapitch666

src/main/java/org/anne/aoc2015/Day16.java

@@ -0,0 +1,61 @@
+package org.anne.aoc2015;
+
+import org.anne.common.Day;
+
+import java.util.*;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class Day16 extends Day {
+    public static void main(String[] args) {
+        new Day16().run();
+    }
+
+    @Override
+    public void execute() {
+        setName("Aunt Sue");
+        List<String> input = readFile();
+        setPart1(part1(input));
+        setPart2(part2(input));
+    }
+
+    private static final Pattern PATTERN = Pattern.compile("Sue (\\d+): (\\w+: \\d+), (\\w+: \\d+), (\\w+: \\d+)");
+    private static final List<String> MFCSAM = List.of("children: 3", "cats: 7", "samoyeds: 2", "pomeranians: 3",
+            "akitas: 0", "vizslas: 0", "goldfish: 5", "trees: 3", "cars: 2", "perfumes: 1");
+
+    public static String part1(List<String> input) {
+        return input.stream()
+                .map(PATTERN::matcher)
+                .filter(Matcher::find)
+                .filter(m -> MFCSAM.contains(m.group(2)) && MFCSAM.contains(m.group(3)) && MFCSAM.contains(m.group(4)))
+                .map(m -> m.group(1))
+                .findFirst()
+                .orElseThrow();
+    }
+
+    public static String part2(List<String> input) {
+        Map<String, Integer> mfcsam = MFCSAM.stream()
+                .map(s -> s.split(": "))
+                .collect(HashMap::new, (m, p) -> m.put(p[0], Integer.parseInt(p[1])), Map::putAll);
+
+        return input.stream()
+                .map(PATTERN::matcher)
+                .filter(Matcher::find)
+                .filter(m -> matchesExpected(m.group(2), mfcsam) && matchesExpected(m.group(3), mfcsam) && matchesExpected(m.group(4), mfcsam))
+                .map(m -> m.group(1))
+                .findFirst()
+                .orElseThrow();
+    }
+
+    private static boolean matchesExpected(String s, Map<String, Integer> map) {
+        var parts = s.split(": ");
+        int actual = Integer.parseInt(parts[1]);
+        int expected = map.get(parts[0]);
+
+        return switch (parts[0]) {
+            case "cats", "trees" -> actual > expected;
+            case "pomeranians", "goldfish" -> actual < expected;
+            default -> actual == expected;
+        };
+    }
+}

src/test/java/org/anne/aoc2015/Day16Test.java

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+package org.anne.aoc2015;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class Day16Test {
+
+    @Test
+    void testPart1() {
+        assertEquals(3, 1 + 2); // No test data available
+    }
+}