[ts] 2024:01: Solve day01

Author: kiriDevs

2024/day01/day01.ts

@@ -0,0 +1,39 @@
+// @ts-ignore - tl_ls is missing @types/node
+import { EOL } from "node:os";
+// @ts-ignore - tl_ls doesn't know about Bun
+const inputLines = (await Bun.file("input").text()).trim().split(EOL);
+
+let left: Array<number> = [];
+let right: Array<number> = [];
+
+class DMap<K> extends Map<K, number> {
+    getOrDefault(inx: K, fallback: number) { return this.get(inx) ?? fallback; }
+    getOrZero(inx: K) { return this.getOrDefault(inx, 0); }
+    increment(inx: K) { this.set(inx, this.getOrZero(inx) + 1); }
+}
+
+inputLines
+    .map((line: string) => line.trim())
+    .forEach((line: string) => {
+        const match = line.match(/(\d+)\s+(\d+)/)!;
+        left.push(parseInt(match[1]));
+        right.push(parseInt(match[2]));
+    });
+left = left.sort();
+right = right.sort();
+
+let solution1 = 0;
+let solution2 = 0;
+
+const rightOccurences: DMap<number> = new DMap();
+for (const inx in left) {
+    const lnum = left[inx];
+    const rnum = right[inx];
+
+    solution1 += Math.abs(lnum - rnum);
+    rightOccurences.increment(rnum);
+}
+
+solution2 = left.reduce((acc, lnum) => acc + (lnum * rightOccurences.getOrZero(lnum)), 0);
+
+console.log(`Part 1: ${solution1}${EOL}Part 2: ${solution2}`);