init d10p2

Day10/Part2.js

@@ -0,0 +1,86 @@
+import { readFileSync } from "fs";
+const t0 = performance.now();
+
+const bends = {
+	"|": [
+		[0, -1],
+		[0, 1],
+	],
+	"-": [
+		[-1, 0],
+		[1, 0],
+	],
+	L: [
+		[0, -1],
+		[1, 0],
+	],
+	J: [
+		[0, -1],
+		[-1, 0],
+	],
+	7: [
+		[-1, 0],
+		[0, 1],
+	],
+	F: [
+		[1, 0],
+		[0, 1],
+	],
+	S: [
+		[1, 0],
+		[0, 1],
+		[-1, 0],
+		[0, -1],
+	],
+};
+const relPos = (pos, x, y) => pos.some((e) => e[0] === x && e[1] === y);
+const compare = (a, b) => a.x === b.x && a.y === b.y;
+
+const input = readFileSync("input.txt")
+	.toString()
+	.split("\n")
+	.filter((e) => e.length > 0)
+	.map((e) => e.split(""));
+const startY = input.findIndex((e) => e.includes("S"));
+const startX = input[startY].findIndex((e) => e === "S");
+
+const open = [
+		{
+			distance: 0,
+			symbol: "S",
+			x: startX,
+			y: startY,
+		},
+	],
+	closed = [];
+while (open.length > 0) {
+	const current = open.shift();
+	closed.push(current);
+
+	const directions = bends[current.symbol];
+	for (let j = -1; j < 2; j++)
+		for (let i = -1; i < 2; i++) {
+			if (!relPos(directions, i, j)) continue;
+
+			const { x, y, distance } = current;
+			const [nx, ny] = [x + i, y + j];
+			const symbol = input[ny][nx];
+			const nd = distance + 1;
+			const next = {
+				distance: nd,
+				symbol,
+				x: nx,
+				y: ny,
+			};
+
+			if (!relPos(bends[symbol], -i, -j)) continue;
+			if (closed.some((e) => compare(e, next))) continue;
+
+			open.push(next);
+		}
+}
+const furthest = closed.sort((a, b) => b.distance - a.distance)[0];
+console.log(furthest.distance);
+
+const t1 = performance.now();
+console.log(`Runtime: ${t1 - t0}ms`);