1 files changed, 42 insertions, 0 deletions
diff --git a/aoc_2021/day-02/part_2.ts b/aoc_2021/day-02/part_2.ts
new file mode 100644
index 0000000..3451ba3
--- /dev/null
+++ b/aoc_2021/day-02/part_2.ts
@@ -0,0 +1,42 @@
+export const main = async (lines: string[]): Promise<number | string> => {
+  const { depth, horiz } = lines
+    .map((line) => line.split(" "))
+    .reduce(
+      (acc, [dir, delta]) => {
+        const d = Number(delta);
+        if (dir === "forward") {
+          acc.horiz += d;
+          acc.depth += acc.aim * d;
+        }
+
+        if (dir === "up") {
+          acc.aim -= d;
+        }
+        if (dir === "down") {
+          acc.aim += d;
+        }
+        return acc;
+      },
+      { horiz: 0, depth: 0, aim: 0 },
+    );
+
+  return depth * horiz;
+};
+
+//
+
+const isrun = process.argv.length > 1 && process.argv[1] === import.meta.path;
+if (isrun) {
+  const file = Bun.file("./problem.txt");
+  const text = await file.text();
+  const lines = text.split("\n");
+
+  console.log("=== COMPUTATION ===\n");
+
+  const answer = await main(lines);
+
+  console.log("\n=== /COMPUTATION ===\n");
+
+  console.log("=== ANSWER TO P2 ===");
+  console.log(answer);
+}