Solve 2024-01

2024/01/2024-01.run.xml

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+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="2024-01" type="BunRunConfiguration">
+    <option name="program" value="2024/01/run.ts" />
+    <option name="workingDirectory" value="$PROJECT_DIR$" />
+    <method v="2" />
+  </configuration>
+</component>

2024/01/index.test.ts

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+import { describe, expect, it } from 'bun:test';
+import { solveFirst, solveSecond } from './index.ts';
+
+const testInput = `3   4
+4   3
+2   5
+1   3
+3   9
+3   3`;
+describe('2024-01', () => {
+  it('first', () => {
+    expect(solveFirst(testInput)).toBe(11);
+  });
+  it('second', () => {
+    expect(solveSecond(testInput)).toBe(31);
+  });
+});

2024/01/index.ts

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+import { groupBy, sumArray } from '../../utils/array.ts';
+
+function splitColumnList(input: string) {
+  const regex = /^(\d*) {3}(\d*)$/gm;
+  const match = input.matchAll(regex);
+
+  const [first, second] = Array.from(
+    match,
+    (m) => [Number(m[1]), Number(m[2])] as [number, number]
+  ).reduce<[number[], number[]]>(
+    ([listA, listB], [a, b]) => {
+      listA.push(a);
+      listB.push(b);
+      return [listA, listB];
+    },
+    [[], []]
+  );
+  return { first, second };
+}
+
+export function solveFirst(input: string): number {
+  const { first, second } = splitColumnList(input);
+
+  first.sort();
+  second.sort();
+
+  const pairs = first.map((e, i) => Math.abs(e - second[i]));
+
+  return sumArray(pairs);
+}
+
+export function solveSecond(input: string): number {
+  const { first, second } = splitColumnList(input);
+
+  const right = groupBy(second, (e) => e);
+
+  const score = first.map(
+    (e) => e * (right.find((r) => r.key === e)?.elements?.length || 0)
+  );
+  return sumArray(score);
+}

2024/01/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);