Solve 2024-18 (using A* lib)

2024/18/2024-18.run.xml

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+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="2024-18" type="BunRunConfiguration">
+    <option name="program" value="2024/18/run.ts" />
+    <option name="workingDirectory" value="$PROJECT_DIR$" />
+    <method v="2" />
+  </configuration>
+</component>

2024/18/index.test.ts

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+import { describe, expect, it } from 'bun:test';
+import { solveFirst, solveSecond } from './index.ts';
+
+describe('2024-18', () => {
+  const testInput = `5,4
+4,2
+4,5
+3,0
+2,1
+6,3
+2,4
+1,5
+0,6
+3,3
+2,6
+5,1
+1,2
+5,5
+2,5
+6,5
+1,4
+0,4
+6,4
+1,1
+6,1
+1,0
+0,5
+1,6
+2,0`;
+  it('first', () => {
+    expect(solveFirst(testInput, 7, 7, 12)).toBe(22);
+  });
+  it('second', () => {
+    expect(solveSecond(testInput, 7, 7, 12)).toBe('6,1');
+  });
+});

2024/18/index.ts

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+// @ts-ignore
+import { astar, Graph } from 'javascript-astar';
+import { replaceChar } from '../../utils/array.ts';
+import {
+  type Coordinate,
+  inBounds,
+  isCoordinateEqual
+} from '../../utils/coordinates.ts';
+import { MultiMap } from '../../utils/multi-map.ts';
+import { PriorityQueue } from '../../utils/queue.ts';
+
+function getGraph(
+  allBytes: [number, number][],
+  byteCount: number,
+  height: number,
+  width: number
+): Graph {
+  const bytes = allBytes.slice(0, byteCount);
+
+  const map = new Array(height)
+    .fill(null)
+    .map((_, y) =>
+      new Array(width)
+        .fill(0)
+        .map((_, x) =>
+          bytes.findIndex((c) => isCoordinateEqual(c, [x, y])) >= 0 ? 0 : 1
+        )
+    );
+
+  return new Graph(map);
+}
+
+export function solveFirst(
+  input: string,
+  width = 71,
+  height = 71,
+  byteCount = 1024
+): number {
+  const match = input.matchAll(/^(\d*),(\d*)/gm);
+
+  const allBytes = Array.from(
+    match,
+    (m) => m.slice(1, 3).map(Number) as Coordinate
+  );
+  const graph = getGraph(allBytes, byteCount, height, width);
+
+  const start = graph.grid[0][0];
+  const end = graph.grid[height - 1][width - 1];
+
+  const result = astar.search(graph, start, end);
+  return result.length;
+}
+
+export function solveSecond(
+  input: string,
+  width = 71,
+  height = 71,
+  byteCount = 1024
+): string {
+  const match = input.matchAll(/^(\d*),(\d*)/gm);
+
+  const allBytes = Array.from(
+    match,
+    (m) => m.slice(1, 3).map(Number) as Coordinate
+  );
+
+  // let lastPath: Coordinates = [];
+  for (let i = byteCount; i < allBytes.length; i++) {
+    const nextByte = allBytes[i];
+    // if (
+    //   lastPath.length > 0 &&
+    //   !lastPath.some((p) => isCoordinateEqual(p, nextByte))
+    // ) {
+    //   console.log(lastPath);
+    //   continue;
+    // }
+
+    const graph = getGraph(allBytes, i + 1, height, width);
+    const start = graph.grid[0][0];
+
+    const end = graph.grid[height - 1][width - 1];
+    const result = astar.search(graph, start, end);
+    if (result.length <= 0) {
+      return nextByte.join(',');
+    }
+    // lastPath = result.map((n: GridNode) => [n.x, n.y] as Coordinate);
+  }
+  return '';
+}
+
+export function solveFirstOld(
+  input: string,
+  width = 71,
+  height = 71,
+  byteCount = 1024
+): number {
+  const match = input.matchAll(/^(\d*),(\d*)/gm);
+
+  const bytes = Array.from(
+    match,
+    (m) => m.slice(1, 3).map(Number) as Coordinate
+  ).slice(0, byteCount);
+
+  const map = new Array(height)
+    .fill(null)
+    .map(() => new Array(width).fill('.').join('') as string);
+
+  bytes.forEach(([x, y]) => replaceChar(map, x, y, '#'));
+  replaceChar(map, width - 1, height - 1, 'E');
+
+  console.log(map.join('\n'));
+  const start = { x: 0, y: 0, score: 0 };
+  const possibleOptions = new PriorityQueue<typeof start>();
+
+  possibleOptions.enqueue(start, 0);
+  const visited = new Set<`${number}:${number}`>();
+  const scores = new MultiMap<number, Coordinate>();
+  visited.add(`${start.x}:${start.y}`);
+
+  let i = 0;
+  while (possibleOptions.size() > 0) {
+    const el = possibleOptions.dequeue()!!;
+
+    scores.multiSet(el.node.score, el.node.y, el.node.x);
+    visited.add(`${el.node.x}:${el.node.y}`);
+    if (map[el.node.y]?.[el.node.x] === 'E') {
+      // console.log(visited);
+      return el.node.score;
+    }
+    if (possibleOptions.size() % 10_000 === 0) {
+      console.log(visited.size, possibleOptions.size());
+    }
+    for (let [x, y] of [
+      [0, 1],
+      [0, -1],
+      [1, 0],
+      [-1, 0]
+    ]) {
+      const nx = el.node.x + x;
+      const ny = el.node.y + y;
+      const score = el.node.score + 1;
+      if (!inBounds(width, height)([nx, ny]) || map[ny]?.[nx] === '#') {
+        continue;
+      }
+      if (visited.has(`${nx}:${ny}`)) {
+        continue;
+      }
+      const existingScore = scores.multiGet(ny, nx) || Number.MAX_SAFE_INTEGER;
+      if (score < existingScore) {
+        possibleOptions.enqueue({ x: nx, y: ny, score }, score);
+      }
+    }
+    // console.log('a', el.node, visited.size, possibleOptions.size());
+    // return 0;
+    i++;
+
+    if (i >= 10_000_000) {
+      visited.forEach((v) => {
+        const [x, y] = v.split(':').map(Number);
+        replaceChar(map, x, y, 'O');
+      });
+      console.log(map.join('\n'));
+      return 0;
+    }
+  }
+  return 0;
+}

2024/18/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);