2025 day 9 part 1 in TypeScript

2025/day09/.gitignore

@@ -0,0 +1 @@
+node_modules

2025/day09/package-lock.json

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+{
+  "name": "day09",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "devDependencies": {
+        "@types/node": "^24.10.2"
+      }
+    },
+    "node_modules/@types/node": {
+      "version": "24.10.2",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-24.10.2.tgz",
+      "integrity": "sha512-WOhQTZ4G8xZ1tjJTvKOpyEVSGgOTvJAfDK3FNFgELyaTpzhdgHVHeqW8V+UJvzF5BT+/B54T/1S2K6gd9c7bbA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "undici-types": "~7.16.0"
+      }
+    },
+    "node_modules/undici-types": {
+      "version": "7.16.0",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-7.16.0.tgz",
+      "integrity": "sha512-Zz+aZWSj8LE6zoxD+xrjh4VfkIG8Ya6LvYkZqtUQGJPZjYl53ypCaUwWqo7eI0x66KBGeRo+mlBEkMSeSZ38Nw==",
+      "dev": true,
+      "license": "MIT"
+    }
+  }
+}

2025/day09/package.json

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+{
+  "type": "module",
+  "devDependencies": {
+    "@types/node": "^24.10.2"
+  }
+}

2025/day09/sample.txt

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+7,1
+11,1
+11,7
+9,7
+9,5
+2,5
+2,3
+7,3

2025/day09/solve.ts

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+#!/usr/bin/env ts-node
+import * as fs from 'fs';
+import { exit } from 'process';
+
+if (process.argv.length < 3) {
+    console.log("Usage: " + process.argv0 + " " + process.argv[1] + " INPUT_FILE");
+    exit(10);
+}
+
+const input_file = fs.readFileSync(process.argv[2], "utf-8");
+const lines = input_file.trim().split("\n");
+
+class Point {
+    x: number;
+    y: number;
+
+    constructor(x: number, y: number) {
+        this.x = x;
+        this.y = y;
+    }
+}
+
+const points = lines.map(line => {
+    const [x, y] = line.split(",");
+    return new Point(+x, +y);
+});
+
+let max_size = 0;
+
+for (let i = 0; i < points.length; ++i) {
+    for (let j = i + 1; j < points.length; ++j) {
+        const width = Math.abs(points[i].x - points[j].x) + 1;
+        const height = Math.abs(points[i].y - points[j].y) + 1;
+
+        max_size = Math.max(max_size, width * height);
+    }
+}
+
+console.log("Part 1:", max_size);