init d8p2

Day8/Part2.js

@@ -0,0 +1,29 @@
+import { readFileSync } from "fs";
+const t0 = performance.now();
+
+const input = readFileSync("input.txt")
+	.toString()
+	.split("\n")
+	.filter((e) => e.length > 0);
+const instructions = input[0].split("");
+const maps = input.slice(1).map((a) => {
+	const [name, pair] = a.split(" = ");
+	const mapping = pair.match(/^\(([A-Z]{3}), ([A-Z]{3})\)$/);
+	const [_, L, R] = mapping;
+	return { name, mapping: { L, R } };
+});
+let count,
+	index = (count = 0);
+let current = maps.find((e) => e.name === "AAA");
+while (current.name !== "ZZZ") {
+	const direction = instructions[index];
+	const mapping = current.mapping[direction];
+
+	current = maps.find((e) => e.name === mapping);
+	index = (index + 1) % instructions.length;
+	count++;
+}
+console.log(count);
+
+const t1 = performance.now();
+console.log(`Runtime: ${t1 - t0}ms`);