Add day 22 of year 2024 🧑‍🎄

2024/days/day-22/README.md

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+# Benchmark
+
+```
+Platform: darwin arm64
+CPU: Apple M3 Pro 11 Cores
+Memory: 18.00 GB
+```
+
+## Sample 1
+
+| part | time (~) | μs                  |
+| ---- | -------- | ------------------- |
+| 1    | 0.49ms   | 0.49287499999999973 |
+| 2    | 4.43ms   | 4.432334000000001   |
+
+## Sample 2
+
+| part | time (~) | μs                   |
+| ---- | -------- | -------------------- |
+| 1    | 0.02ms   | 0.024167000000002048 |
+| 2    | 3.28ms   | 3.280583             |
+
+## Answer
+
+| part | time (~) | μs                |
+| ---- | -------- | ----------------- |
+| 1    | 8.46ms   | 8.462292000000001 |
+| 2    | 692.41ms | 692.41475         |

2024/days/day-22/in.sample.1.txt

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+1
+10
+100
+2024

2024/days/day-22/in.sample.2.txt

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+1
+2
+3
+2024

2024/days/day-22/main.js

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+const fs = require('fs');
+
+function parse(source) {
+  return source.trim().split('\n').map(Number);
+}
+
+const N = 2000;
+
+function gen(seed) {
+  const offset = 16777215;
+  seed ^= (seed << 6) & offset;
+  seed ^= (seed >> 5) & offset;
+  seed ^= (seed << 11) & offset;
+  return seed;
+}
+
+function genNth(seed, n) {
+  while (n--) {
+    seed = gen(seed);
+  }
+  return seed;
+}
+
+const next = (seed) => {
+  const newSeed = gen(seed);
+  return {
+    seed: newSeed,
+    price: newSeed % 10,
+    change: (newSeed % 10) - (seed % 10),
+  };
+};
+
+function genSequences(seed, N) {
+  const m = new Map();
+
+  const window = new Array(4).fill(null);
+  for (let i = 0; i < window.length; ++i) {
+    window[i] = next(window[i - 1]?.seed ?? seed);
+  }
+
+  for (let i = 4; i < N - 1; ++i) {
+    const hash = window.map(({ change }) => change).join(',');
+    const prev = window.at(-1);
+    m.set(hash, Math.max(m.get(hash) ?? 0, prev.price));
+    window.push(next(prev.seed));
+    window.shift();
+  }
+
+  return m;
+}
+
+function getMaxBananas(seeds, N) {
+  const m = new Map();
+  let max = 0;
+  seeds.forEach((seed) =>
+    genSequences(seed, N)
+      .entries()
+      .forEach(([hash, value]) => {
+        const sum = (m.get(hash) ?? 0) + value;
+        max = Math.max(sum, max);
+        m.set(hash, sum);
+      })
+  );
+  return max;
+}
+
+function part1(data) {
+  return Number(data.reduce((sum, seed) => sum + genNth(seed, N), 0));
+}
+
+function part2(data) {
+  return getMaxBananas(data, N);
+}
+
+module.exports = { parse, part1, part2 };