feat: day 8 (#11)

* use camelCase

* day 8 setup

* day 8 done

day2/mod.ts

@@ -4,7 +4,7 @@ export function parse(data: string): number[][] {
   );
 }
 
-function is_safe(report: number[]): boolean {
+function isSafe(report: number[]): boolean {
   const diffs = Array.from(
     { length: report.length - 1 },
     (_, i) => report[i + 1] - report[i],
@@ -20,7 +20,7 @@ function is_safe(report: number[]): boolean {
 }
 
 export function solve1(data: number[][]): number {
-  return data.filter(is_safe)
+  return data.filter(isSafe)
     .length;
 }
 
@@ -29,7 +29,7 @@ export function solve2(data: number[][]): number {
     Array.from(
       { length: report.length },
       (_, i) => report.slice(0, i).concat(report.slice(i + 1)),
-    ).some(is_safe)
+    ).some(isSafe)
   ).length;
 }
 

day8/deno.json

@@ -0,0 +1,7 @@
+{
+  "name": "@scope/day8",
+  "version": "0.1.0",
+  "exports": {
+    ".": "./mod.ts"
+  }
+}

day8/example.txt

@@ -0,0 +1,12 @@
+............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............

day8/mod.ts

@@ -0,0 +1,68 @@
+export function parse(data: string): string[][] {
+  return data.trim().split("\n").map((line) => line.trim().split(""));
+}
+
+export function solve(rdata: string[][], bound: [number, number]): number {
+  const data = rdata.map((row) => row.slice());
+  const height = data.length;
+  const width = data[0].length;
+  const charLocs = new Map<string, [number, number][]>();
+  for (let y = 0; y < width; y++) {
+    for (let x = 0; x < height; x++) {
+      const char = data[y][x];
+      if (char === ".") continue;
+      if (!charLocs.has(char)) {
+        charLocs.set(char, []);
+      }
+      charLocs.get(char)!.push([x, y]);
+    }
+  }
+
+  for (const [_, locs] of charLocs) {
+    for (let i = 0; i < locs.length; i++) {
+      for (let j = 0; j < locs.length; j++) {
+        if (i === j) continue;
+
+        const [x1, y1] = locs[i];
+        const [x2, y2] = locs[j];
+
+        // point1 -> point2
+        for (let h = bound[0]; h <= bound[1]; h++) {
+          const [ax1, ay1] = [x1 + h * (x1 - x2), y1 + h * (y1 - y2)];
+          if (0 <= ax1 && ax1 < width && 0 <= ay1 && ay1 < height) {
+            data[ay1][ax1] = "#";
+          } else {
+            break;
+          }
+        }
+      }
+    }
+  }
+
+  let count = 0;
+
+  for (let y = 0; y < width; y++) {
+    for (let x = 0; x < height; x++) {
+      if (data[y][x] === "#") {
+        count++;
+      }
+    }
+  }
+
+  return count;
+}
+
+export function solve1(data: string[][]): number {
+  return solve(data, [1, 1]);
+}
+
+export function solve2(data: string[][]): number {
+  return solve(data, [0, Infinity]);
+}
+
+if (import.meta.main) {
+  const dataPath = new URL("input.txt", import.meta.url).pathname;
+  const data = parse(await Deno.readTextFile(dataPath));
+  console.log(solve1(data));
+  console.log(solve2(data));
+}

day8/test.ts

@@ -0,0 +1,9 @@
+import { assertEquals } from "@std/assert";
+import { parse, solve1, solve2 } from "./mod.ts";
+
+Deno.test(async function testExample() {
+  const dataPath = new URL("example.txt", import.meta.url).pathname;
+  const data = parse(await Deno.readTextFile(dataPath));
+  assertEquals(solve1(data), 14);
+  assertEquals(solve2(data), 34);
+});