Add day 14 of year 2024 🎄

2024/days/day-14/README.md

@@ -0,0 +1,21 @@
+# Benchmark
+
+```
+Platform: darwin arm64
+CPU: Apple M3 Pro 11 Cores
+Memory: 18.00 GB
+```
+
+## Sample 1
+
+| part | time (~) | μs                |
+| ---- | -------- | ----------------- |
+| 1    | 0.35ms   | 0.351707999999995 |
+| 2    | 7.75ms   | 7.748540999999996 |
+
+## Answer
+
+| part | time (~) | μs                 |
+| ---- | -------- | ------------------ |
+| 1    | 0.19ms   | 0.1948330000000027 |
+| 2    | 645.41ms | 645.405041         |

2024/days/day-14/in.sample.txt

@@ -0,0 +1,14 @@
+11 7
+
+p=0,4 v=3,-3
+p=6,3 v=-1,-3
+p=10,3 v=-1,2
+p=2,0 v=2,-1
+p=0,0 v=1,3
+p=3,0 v=-2,-2
+p=7,6 v=-1,-3
+p=3,0 v=-1,-2
+p=9,3 v=2,3
+p=7,3 v=-1,2
+p=2,4 v=2,-3
+p=9,5 v=-3,-3

2024/days/day-14/main.js

@@ -0,0 +1,125 @@
+function parse(source) {
+  const [size, robots] = source.trim().split('\n\n');
+  return {
+    size: size.split(' ').map(Number),
+    robots: robots.split('\n').map((segment) => {
+      const [, px, py, vx, vy] = segment.match(
+        /p=(-?\d+),(-?\d+)\sv=(-?\d+),(-?\d+)/
+      );
+      return {
+        p: [Number(px), Number(py)],
+        v: [Number(vx), Number(vy)],
+      };
+    }),
+  };
+}
+
+function mod(a, b) {
+  return ((a % b) + b) % b;
+}
+
+function wrap(len, p, v, seconds) {
+  return mod(p + v * seconds, len);
+}
+
+function simulate(lenX, lenY, robots, seconds) {
+  return robots.map(({ p: [px, py], v: [vx, vy] }) => {
+    return {
+      p: [wrap(lenX, px, vx, seconds), wrap(lenY, py, vy, seconds)],
+      v: [vx, vy],
+    };
+  });
+}
+
+function countInArea(x0, y0, x1, y1, robots) {
+  return robots.filter(
+    (robot) =>
+      robot.p[0] >= x0 &&
+      robot.p[0] <= x1 &&
+      robot.p[1] >= y0 &&
+      robot.p[1] <= y1
+  ).length;
+}
+
+function getQuadrants(sizeX, sizeY) {
+  const midX = Math.floor(sizeX / 2);
+  const midY = Math.floor(sizeY / 2);
+  return [
+    [
+      [0, 0],
+      [midX - 1, midY - 1],
+    ],
+    [
+      [midX + 1, 0],
+      [sizeX - 1, midY - 1],
+    ],
+    [
+      [0, midY + 1],
+      [midX - 1, sizeY - 1],
+    ],
+    [
+      [midX + 1, midY + 1],
+      [sizeX - 1, sizeY - 1],
+    ],
+  ];
+}
+
+function createGrid(sizeX, sizeY, robots) {
+  return robots
+    .reduce(
+      (grid, { p: [px, py] }) => {
+        grid[py][px] = '#';
+        return grid;
+      },
+      new Array(sizeY).fill(null).map(() => new Array(sizeX).fill('.'))
+    )
+    .map((row) => row.join(''))
+    .join('\n');
+}
+
+function getEntropyScore(robots) {
+  let score = 0;
+  [...robots]
+    .sort(({ p: [x1, y1] }, { p: [x2, y2] }) =>
+      x1 === x2 ? -1 : y1 === y2 ? -1 : 1
+    )
+    .forEach(({ p: [x1, y1] }, i, arr) => {
+      if (i !== 0) {
+        const [x2, y2] = arr[i - 1].p;
+        score += ((x1 + 1) / (x2 + 1)) * ((y1 + 1) / (y2 + 1));
+      }
+    });
+  return score;
+}
+
+function part1(data) {
+  const seconds = 100;
+  const robots = simulate(data.size[0], data.size[1], data.robots, seconds);
+
+  const quads = getQuadrants(data.size[0], data.size[1]);
+  return quads.reduce(
+    (acc, [[x0, y0], [x1, y1]]) => acc * countInArea(x0, y0, x1, y1, robots),
+    1
+  );
+}
+
+function part2(data) {
+  let bestMatch = [-1, Infinity, []];
+  for (let i = 0; i < data.size[0] * data.size[1]; ++i) {
+    const robots = simulate(data.size[0], data.size[1], data.robots, i);
+    const entropyScore = getEntropyScore(robots);
+    if (entropyScore < bestMatch[1]) {
+      bestMatch = [i, entropyScore, robots];
+    }
+  }
+
+  const grid = createGrid(data.size[0], data.size[1], bestMatch[2]);
+
+  console.log(
+    `seconds: ${bestMatch[0]}, entropy: ${bestMatch[1]}\n${grid}\n\n`
+  );
+
+  return bestMatch[0];
+}
+
+module.exports = { parse, part1, part2 };