Day 22 Part 1 solution

bin/aoc.dart

@@ -19,6 +19,7 @@ import 'day18.dart' as day18;
 import 'day19.dart' as day19;
 import 'day20.dart' as day20;
 import 'day21.dart' as day21;
+import 'day22.dart' as day22;
 
 void main(List<String> arguments) async {
   print('');
@@ -44,6 +45,7 @@ void main(List<String> arguments) async {
     day19.main,
     day20.main,
     day21.main,
+    day22.main,
   ]) {
     await day(arguments);
     print('');

bin/day22.dart

@@ -0,0 +1,10 @@
+import 'package:aoc_2024/lib.dart';
+import 'package:aoc_2024/day22/part_1.dart' as part1;
+
+Future<void> main(List<String> arguments) async {
+  await runDay(
+    day: Day.day22,
+    part1: part1.calculate,
+    part2: (_) => Future.value(0),
+  );
+}

lib/day22/part_1.dart

@@ -0,0 +1,28 @@
+import 'dart:io';
+
+import 'package:collection/collection.dart';
+
+import 'shared.dart';
+
+/// --- Day 22: Monkey Market ---
+///
+/// Determine the numbers generated by monkeys at an auction.
+/// Each monkey starts with a secret number, and generates their
+/// next number based on a defined set of operations.
+///
+/// Return the sum of all secret numbers after 2000 iterations.
+Future<int> calculate(File file) async {
+  final data = await loadData(file);
+
+  return data.map((s) => _simulate(s, 2000)).sum;
+}
+
+/// Generate the secret number after [iterations], starting at
+/// the given [starting] secret number.
+int _simulate(int starting, int iterations) {
+  int secret = starting;
+  for (int i = 0; i < iterations; i++) {
+    secret = nextSecret(secret);
+  }
+  return secret;
+}

lib/day22/shared.dart

@@ -0,0 +1,15 @@
+import 'dart:io';
+
+/// Calculates the next secret number after the given [secret].
+int nextSecret(int secret) {
+  int next = secret;
+  next = ((next * 64) ^ next) % 16777216;
+  next = ((next ~/ 32) ^ next) % 16777216;
+  return ((next * 2048) ^ next) % 16777216;
+}
+
+/// Loads the list of starting secret numbers.
+Future<List<int>> loadData(File file) async {
+  final lines = await file.readAsLines();
+  return lines.map(int.parse).toList();
+}

resources/sample_data/day22.txt

@@ -0,0 +1,4 @@
+1
+10
+100
+2024

test/day22_test.dart

@@ -0,0 +1,25 @@
+import 'package:aoc_2024/lib.dart';
+import 'package:aoc_2024/day22/part_1.dart' as part1;
+import 'package:test/test.dart';
+
+void main() {
+  final day = Day.day22;
+
+  group('sample data', tags: 'sample-data', () {
+    final resources = Resources.sample;
+    final file = resources.file(day);
+
+    test('part1', () async {
+      expect(await part1.calculate(file), 37327623);
+    });
+  });
+
+  group('real data', tags: 'real-data', () {
+    final resources = Resources.real;
+    final file = resources.file(day);
+
+    test('part1', () async {
+      expect(await part1.calculate(file), 15608699004);
+    });
+  });
+}