prettier

2022/08/part1.js

@@ -10,6 +10,12 @@ const readInput = (...args) =>
     .filter((x) => x)
     .map((l) => l.split("").map((x) => parseInt(x)));
 
+export const outOfBound = (size) => (pos) => {
+  if (Math.min(pos.x, pos.y) < 0) return true;
+  if (Math.max(pos.x, pos.y) >= size) return true;
+  return false;
+};
+
 export function generateVisibilityGrid(forest) {
   const size = forest.length;
   const visibility = Array(size)
@@ -47,17 +53,11 @@ export function generateVisibilityGrid(forest) {
     }))
   );
 
-  const outOfBound = (pos) => {
-    if (Math.min(pos.x, pos.y) < 0) return true;
-    if (Math.max(pos.x, pos.y) >= size) return true;
-    return false;
-  };
-
   while (positions.length) {
     const pos = positions.shift();
     pos.position.add(pos.inc);
 
-    if (outOfBound(pos.position)) continue;
+    if (outOfBound(size)(pos.position)) continue;
 
     if (forest[pos.position.x][pos.position.y] > pos.height) {
       visibility[pos.position.x][pos.position.y] = true;
@@ -73,7 +73,7 @@ export function generateVisibilityGrid(forest) {
 export const puzzleInput = readInput(import.meta.url, "input");
 export const sample = readInput(import.meta.url, "sample");
 
-function printMap(forest) {
+export function printMap(forest) {
   forest.forEach((line) => console.log(line.join(" ")));
   return forest;
 }

2022/08/part2.js

@@ -1,4 +1,50 @@
 import * as R from "remeda";
+import memo from "memoizerific";
+import Victor from "@a-robu/victor";
 
+import { printMap, outOfBound } from "./part1";
 
-export default () => {};
+const V = (...args) => new Victor(...args);
+
+function visibility(forest, x, y, dx, dy) {
+  const pos = V(x, y);
+  const inc = V(dx, dy);
+
+  let vis = 0;
+
+  while (true) {
+    pos.add(inc);
+    if (outOfBound(forest.length)(pos)) return vis;
+
+    if (forest[x][y] <= forest[pos.x][pos.y]) return 1 + vis;
+    vis++;
+  }
+}
+
+const visibilityAround = (forest) => (x, y) => {
+  return [
+    [0, 1],
+    [0, -1],
+    [1, 0],
+    [-1, 0],
+  ]
+    .map((d) => visibility(forest, x, y, ...d))
+    .reduce((a, b) => a * b);
+};
+
+export default R.createPipe(
+  (forest) => {
+    const viz = Array(forest.length)
+      .fill(null)
+      .map(() => Array(forest.length).fill(0));
+
+    for (const x of R.range(0, forest.length)) {
+      for (const y of R.range(0, forest.length)) {
+        viz[x][y] = visibilityAround(forest)(x, y);
+      }
+    }
+    return viz;
+  },
+  R.flatten,
+  R.maxBy(R.identity)
+);

2022/08/test.js

@@ -1,21 +1,25 @@
 import { test, expect, describe } from "vitest";
 
 import { expectSolution } from "../01/main.js";
-import part1, { sample, puzzleInput, generateVisibilityGrid } from "./part1.js";
+import part1, { sample, puzzleInput } from "./part1.js";
 import part2 from "./part2.js";
 
 describe("part 1", () => {
-    test( "sample", () => {
-        expect( part1(sample) ).toBe(21);
-
-    });
+  test("sample", () => {
+    expect(part1(sample)).toBe(21);
+  });
   test("solution", () => {
     expectSolution(part1(puzzleInput)).toEqual(1703);
   });
 });
 
 describe("part 2", () => {
-  test.todo("solution", () => {
-    expectSolution(part2(puzzleInput)).toEqual("TODO");
+  test("sample", () => {
+    expect(part2(sample)).toBe(8);
+  });
+  test("solution", () => {
+    const solution = part2(puzzleInput);
+    expect(solution).toBeGreaterThan(160);
+    expectSolution(solution).toEqual(496650);
   });
 });