Solve 2024-08

2024/08/2024-08.run.xml

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+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="2024-08" type="BunRunConfiguration">
+    <option name="program" value="2024/08/run.ts" />
+    <option name="workingDirectory" value="$PROJECT_DIR$" />
+    <method v="2" />
+  </configuration>
+</component>

2024/08/index.test.ts

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+import { describe, expect, it } from 'bun:test';
+import { solveFirst, solveSecond } from './index.ts';
+
+describe('2024-08', () => {
+  const testInput = `............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............`;
+  it('first', () => {
+    expect(solveFirst(testInput)).toBe(14);
+  });
+  it('second', () => {
+    const secondTest = `T.........
+...T......
+.T........
+..........
+..........
+..........
+..........
+..........
+..........
+..........`;
+    expect(solveSecond(testInput)).toBe(34);
+    expect(solveSecond(secondTest)).toBe(9);
+  });
+});

2024/08/index.ts

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+import { combinations, unique } from '../../utils/array.ts';
+import { inBounds, isCoordinateEqual } from '../../utils/coordinates.ts';
+
+export function solveFirst(input: string): number {
+  const rows = input.split('\n');
+
+  const antennas = new Map<string, [number, number][]>();
+
+  for (let y = 0; y < rows.length; y++) {
+    for (let x = 0; x < rows[y].length; x++) {
+      const digit = rows[y][x];
+      if (digit === '.') {
+        continue;
+      }
+      const entry = antennas.get(digit) || [];
+      entry.push([x, y]);
+      antennas.set(digit, entry);
+    }
+  }
+  const antiNodes: [number, number][] = [];
+
+  // console.log(rows);
+  // console.log(antennas);
+  antennas.forEach((positions) => {
+    combinations(positions).forEach(({ a, b }) =>
+      antiNodes.push([a[0] - (b[0] - a[0]), a[1] - (b[1] - a[1])])
+    );
+  });
+
+  const validAntiNodes = antiNodes
+    .filter(inBounds(rows[0].length, rows.length))
+    .filter(unique(isCoordinateEqual));
+
+  // validAntiNodes.forEach(([x, y]) => rows[y][x] === '.' && replaceChar(rows, x, y, '#'));
+  //
+  // console.log(rows.join('\n'));
+  return validAntiNodes.length;
+}
+
+export function solveSecond(input: string): number {
+  const rows = input.split('\n');
+
+  const antennas = new Map<string, [number, number][]>();
+
+  const yMax = rows.length;
+  const xMax = rows[0].length;
+
+  for (let y = 0; y < yMax; y++) {
+    for (let x = 0; x < xMax; x++) {
+      const digit = rows[y][x];
+      if (digit === '.') {
+        continue;
+      }
+      const entry = antennas.get(digit) || [];
+      entry.push([x, y]);
+      antennas.set(digit, entry);
+    }
+  }
+  const antiNodes: [number, number][] = [];
+
+  antennas.forEach((positions) => {
+    combinations(positions).forEach(({ a, b }) => {
+      for (let y = 0; y < yMax; y++) {
+        antiNodes.push([a[0] + (b[0] - a[0]) * y, a[1] + (b[1] - a[1]) * y]);
+      }
+    });
+  });
+
+  const validAntiNodes = antiNodes
+    .filter(inBounds(rows[0].length, rows.length))
+    .filter(unique(isCoordinateEqual));
+
+  // console.log(validAntiNodes);
+  // validAntiNodes.forEach(
+  //   ([x, y]) => rows[y][x] === '.' && replaceChar(rows, x, y, '#')
+  // );
+  //
+  // console.log(rows.join('\n'));
+
+  return validAntiNodes.length;
+}

2024/08/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);