Solve 2024-22

2024/22/2024-22.run.xml

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+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="2024-22" type="BunRunConfiguration">
+    <option name="program" value="2024/22/run.ts" />
+    <option name="workingDirectory" value="$PROJECT_DIR$" />
+    <method v="2" />
+  </configuration>
+</component>

2024/22/index.test.ts

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+import { describe, expect, it } from 'bun:test';
+import { solveFirst, solveSecond } from './index.ts';
+
+describe('2024-22', () => {
+  it('first', () => {
+    const testInput = `1
+10
+100
+2024`;
+    expect(solveFirst(testInput)).toBe(37327623);
+  });
+  it('second', () => {
+    // it takes too long
+    // so only run while `NODE_ENV=production bun test --coverage`
+    if (process.env.NODE_ENV === 'production') {
+      const testInput = `1
+2
+3
+2024`;
+      expect(solveSecond(testInput)).toBe(23);
+    }
+  });
+});

2024/22/index.ts

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+import { Presets, SingleBar } from 'cli-progress';
+import { sumArray } from '../../utils/array.ts';
+import { mod } from '../../utils/numbers.ts';
+
+export function solveFirst(input: string): number {
+  const start = input.split('\n').map(Number);
+
+  const end = start.map((v) => {
+    let value = v;
+    for (let i = 0; i < 2000; i++) {
+      value = mod((value * 64) ^ value, 16777216);
+      value = mod(Math.floor(value / 32) ^ value, 16777216);
+      value = mod((value * 2048) ^ value, 16777216);
+    }
+    return value;
+  });
+  return sumArray(end);
+}
+
+type Sequence = [number, number, number, number];
+
+function findPriceBySequence(
+  prices: [number, number][],
+  sequence: Sequence
+): number {
+  return (
+    prices.find(
+      (p, i, a) => i >= 4 && sequence.every((s, si) => s === a[i - (3 - si)][1])
+    )?.[0] || 0
+  );
+}
+
+function getSequences(prices: [number, number][]): string[] {
+  const sequences = new Array<string>(prices.length - 4);
+  for (let i = 4; i < prices.length; i++) {
+    sequences[i - 4] = [
+      prices[i - 3][1],
+      prices[i - 2][1],
+      prices[i - 1][1],
+      prices[i][1]
+    ].join(',');
+  }
+  return sequences;
+}
+
+export function solveSecond(input: string): number {
+  const start = input.split('\n').map(Number);
+
+  const prices = start.map((v) => {
+    let value = v;
+    const sec = new Array<[number, number]>(2000);
+    sec[0] = [mod(value, 10), 0];
+    let lastPrice = sec[0][0];
+    for (let i = 0; i < 2000; i++) {
+      value = mod((value * 64) ^ value, 16777216);
+      value = mod(Math.floor(value / 32) ^ value, 16777216);
+      value = mod((value * 2048) ^ value, 16777216);
+      const price = mod(value, 10);
+      sec[i + 1] = [price, price - lastPrice];
+      lastPrice = price;
+    }
+    return sec;
+  });
+
+  const sequences = prices.flatMap((p) => getSequences(p));
+  const uniqueSequences = new Set(sequences);
+  const bar =
+    process.env.NODE_ENV === 'test'
+      ? null
+      : new SingleBar({}, Presets.shades_classic);
+  bar?.start(uniqueSequences.size, 0);
+  let highestPrice = 0;
+
+  for (let sequence of uniqueSequences) {
+    const numSequence = sequence.split(',').map(Number) as Sequence;
+    const finalPrices = sumArray(
+      prices.map((p) => findPriceBySequence(p, numSequence))
+    );
+
+    if (finalPrices > highestPrice) {
+      highestPrice = finalPrices;
+    }
+    bar?.increment();
+  }
+  bar?.stop();
+
+  return highestPrice;
+}

2024/22/run.ts

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+import { join } from 'path';
+import { solveFirst, solveSecond } from './index.ts';
+
+const input = await Bun.file(join(__dirname, 'input.txt')).text();
+
+const firstAnswer = solveFirst(input);
+
+console.log(firstAnswer);
+
+const secondAnswer = solveSecond(input);
+
+console.log(secondAnswer);