1 files changed, 30 insertions, 0 deletions
diff --git a/day-4/script.ts b/day-4/script.ts
new file mode 100644
index 0000000..53488b5
--- /dev/null
+++ b/day-4/script.ts
@@ -0,0 +1,30 @@
+import fs from "fs";
+
+// Quick implementation of _.chunks
+function chunks<T>(data: Array<T>, chunkSize: number) {
+  return data.reduce((acc, value, index) => {
+    // Initialize a new chunk
+    if (index % chunkSize === 0) acc.push([]);
+    acc[acc.length - 1].push(value);
+    return acc;
+  }, [] as T[][]);
+}
+
+function parseNumbers(s: string) {
+  return chunks(s.split(""), 3).map((chunk) => Number(chunk.join("")));
+}
+
+const result = fs
+  .readFileSync("./input.txt")
+  .toString()
+  .split("\n")
+  .slice(0, -1)
+  .map((line) => {
+    const [_cardStr, dataStr] = line.split(": ");
+    const [winning, existing] = dataStr.split("| ").map(parseNumbers);
+    return { winning, existing };
+  })
+  .map((data) => data.existing.filter((x) => data.winning.includes(x)).length)
+  .reduce((acc, winCount) => acc + (winCount ? 2 ** (winCount - 1) : 0), 0);
+
+console.log({ result });