1 files changed, 62 insertions, 0 deletions
diff --git a/aoc_2023/day-04/part_2.ts b/aoc_2023/day-04/part_2.ts
new file mode 100644
index 0000000..e50f14d
--- /dev/null
+++ b/aoc_2023/day-04/part_2.ts
@@ -0,0 +1,62 @@
+export const main = async (lines: string[]): Promise<number | string> => {
+  let card = 0;
+  const counts = new Map<number, number>();
+  lines.forEach((_, i) => counts.set(i, 1));
+
+  for (const line of lines) {
+    const [cardS, numbersS] = line.split(" | ");
+    const cardNums = cardS
+      .split(":")
+      .at(1)!
+      .split(" ")
+      .filter((x) => x)
+      .map((x) => x.trim())
+      .map((x) => parseInt(x));
+    const winners = numbersS
+      .split(" ")
+      .filter((x) => x)
+      .map((x) => x.trim())
+      .map((x) => parseInt(x));
+
+    const winnerSet = new Set<number>(winners);
+    const wins = cardNums.reduce(
+      (acc, x) => acc + (winnerSet.has(x) ? 1 : 0),
+      0
+    );
+
+    const currCardCount = counts.get(card) ?? 1;
+
+    for (let _ = 0; _ < currCardCount; _++) {
+      for (let i = 1; i <= Math.min(wins, lines.length - 1); i++) {
+        const currCount = counts.get(card + i) ?? 1;
+        counts.set(card + i, currCount + 1);
+      }
+    }
+
+    card++;
+  }
+
+  console.log(counts);
+
+  return Array.from(counts.keys())
+    .map((x) => counts.get(x)!)
+    .reduce((acc, x) => acc + x, 0);
+};
+
+//
+
+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").filter((x) => x && x.length);
+
+  console.log("=== COMPUTATION ===\n");
+
+  const answer = await main(lines);
+
+  console.log("\n=== /COMPUTATION ===\n");
+
+  console.log("=== ANSWER TO P2 ===");
+  console.log(answer);
+}