feat(js): add solutions for 2024 day 18

js/src/2024/18/index.js

@@ -0,0 +1,52 @@
+import { Grid, astar, bisect, solution } from '../../utils/index.js';
+
+const EMPTY = '.';
+const CORRUPTED = '#';
+
+const isEmpty = (point) => point.value === EMPTY;
+
+const parse = (input) =>
+  input
+    .trim()
+    .split('\n')
+    .map((line) => line.split(',').map(Number));
+
+const simulate = (bytes, size) => {
+  const memspace = new Grid();
+  memspace.fill(0, 0, size, size, EMPTY);
+  for (const [x, y] of bytes) {
+    memspace.set(x, y, CORRUPTED);
+  }
+  return memspace;
+};
+
+const speedrun = (memspace, size) => {
+  const start = memspace.getPoint(0, 0);
+  const goal = memspace.getPoint(size, size);
+
+  return astar(start, goal, {
+    neighborsFor: (current) => current.adjacentNeighbors.filter(isEmpty),
+  });
+};
+
+export const partOne = solution((input, { size = 70, numBytes = 1024 }) => {
+  const bytes = parse(input).slice(0, numBytes);
+  const memspace = simulate(bytes, size);
+  return speedrun(memspace, size).score;
+});
+
+export const partTwo = solution(async (input, { size = 70 }) => {
+  const bytes = parse(input);
+
+  const result = await bisect({
+    lower: 1,
+    upper: bytes.length,
+    until: (index) => {
+      const memspace = simulate(bytes.slice(0, index), size);
+      const candidate = speedrun(memspace, size);
+      return !candidate;
+    },
+  });
+
+  return bytes[result - 1].join(',');
+});

puzzles/2024/18/examples.yaml

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+part-one:
+  - input: &example1 |
+      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
+    answer: 22
+    args:
+      size: 6
+      num-bytes: 12
+
+part-two:
+  - input: *example1
+    answer: 6,1
+    args:
+      size: 6