Day 14

14/part1.js

@@ -0,0 +1,50 @@
+const { readFileSync } = require("fs");
+// Parse Input
+const inputFile = "input.txt";
+const input = readFileSync(inputFile).toString().trim();
+const robots = [];
+
+const GRID_WIDTH = 101;
+const GRID_HEIGHT = 103;
+
+input.split("\n").forEach((line) => {
+  const regex = /-?\d+/g;
+  const values = line.match(regex).map((x) => parseInt(x));
+
+  robots.push({
+    id: robots.length,
+    position: [values[0], values[1]],
+    velocity: [values[2], values[3]],
+  });
+});
+
+function tick() {
+  robots.forEach((robot) => {
+    let x = (robot.position[0] + robot.velocity[0]) % GRID_WIDTH;
+    let y = (robot.position[1] + robot.velocity[1]) % GRID_HEIGHT;
+
+    if (x < 0) x = GRID_WIDTH + x;
+    if (y < 0) y = GRID_HEIGHT + y;
+
+    robot.position = [x, y];
+  });
+}
+
+for (let i = 0; i < 100; i++) {
+  tick();
+}
+
+let quadrants = [0, 0, 0, 0];
+let halfWidth = Math.floor(GRID_WIDTH / 2);
+let halfHeight = Math.floor(GRID_HEIGHT / 2);
+
+robots.forEach((robot) => {
+  let [x, y] = robot.position;
+  if (x < halfWidth && y < halfHeight) quadrants[0]++;
+  if (x > halfWidth && y < halfHeight) quadrants[1]++;
+  if (x > halfWidth && y > halfHeight) quadrants[2]++;
+  if (x < halfWidth && y > halfHeight) quadrants[3]++;
+});
+
+let result = quadrants.reduce((acc, num) => acc * num, 1);
+console.log(result);

14/part2.js

@@ -0,0 +1,75 @@
+const { readFileSync } = require("fs");
+const readline = require("readline");
+
+// Parse Input
+const inputFile = "input.txt";
+const input = readFileSync(inputFile).toString().trim();
+const robots = [];
+
+const GRID_WIDTH = 101;
+const GRID_HEIGHT = 103;
+
+input.split("\n").forEach((line) => {
+  const regex = /-?\d+/g;
+  const values = line.match(regex).map((x) => parseInt(x));
+
+  robots.push({
+    id: robots.length,
+    position: [values[0], values[1]],
+    velocity: [values[2], values[3]],
+  });
+});
+
+function displayGrid() {
+  const grid = Array.from({ length: GRID_HEIGHT }, () =>
+    Array(GRID_WIDTH).fill(0)
+  );
+
+  robots.forEach((robot) => {
+    grid[robot.position[1]][robot.position[0]]++;
+  });
+
+  grid.forEach((line) => {
+    console.log(line.map((x) => (x == 0 ? "." : x.toString())).join(""));
+  });
+  console.log("Elapsed Seconds", elapsedSeconds);
+}
+
+function computeVariations() {
+  let totalDistance = 0;
+
+  let coords = robots.map((r) => r.position);
+
+  for (let i = 1; i < coords.length; i++) {
+    const x1 = coords[i - 1][0];
+    const y1 = coords[i - 1][1];
+    const x2 = coords[i][0];
+    const y2 = coords[i][1];
+
+    totalDistance += Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
+  }
+
+  return totalDistance / (coords.length - 1);
+}
+
+function tick() {
+  robots.forEach((robot) => {
+    let x = (robot.position[0] + robot.velocity[0]) % GRID_WIDTH;
+    let y = (robot.position[1] + robot.velocity[1]) % GRID_HEIGHT;
+
+    if (x < 0) x = GRID_WIDTH + x;
+    if (y < 0) y = GRID_HEIGHT + y;
+
+    robot.position = [x, y];
+  });
+}
+
+let elapsedSeconds = 0;
+while (true) {
+  tick();
+  elapsedSeconds++;
+  if (computeVariations() < 40) {
+    displayGrid();
+    break;
+  }
+}