[TASK] Finished Day 13 + some style fixes to make sure eslint is happy enough to deploy to firebase functions

functions/src/day11.ts

@@ -112,7 +112,7 @@ class OctopusGrid {
 
   toString(): string {
 
-    let lines = [];
+    const lines = [];
     for (let y = 0; y < this.maxY; y++) {
       let line = "";
       for (let x = 0; x < this.maxX; x++) {

functions/src/day12.ts

@@ -28,7 +28,7 @@ class Day12 implements Day {
     return caves;
   }
 
-  addPath(from: string, to: string, caves: Map<string, string[]>) {
+  addPath(from: string, to: string, caves: Map<string, string[]>): void {
     const existing = caves.get(from);
     if (existing) {
       existing.push(to);
@@ -37,7 +37,7 @@ class Day12 implements Day {
     }
   }
 
-  countPaths(pos: string, caves: Map<string, string[]>, visited: string[], secondSmallVisitAllowed: boolean = false): number {
+  countPaths(pos: string, caves: Map<string, string[]>, visited: string[], secondSmallVisitAllowed = false): number {
 
     // If we reached the end, there is exactly one path
     if (pos === "end") return 1;
@@ -64,7 +64,7 @@ class Day12 implements Day {
     return sum;
   }
 
-  isSmall(cave: string) {
+  isSmall(cave: string): boolean {
     return cave.toLowerCase() === cave;
   }
 }

functions/src/day13.ts

@@ -0,0 +1,100 @@
+import Day from "./day";
+import Vector2 from "./vector2";
+
+class Day13 implements Day {
+
+  part1(input: string[]): number | string {
+
+    const {dots, folds} = this.parseInput(input);
+
+    const foldedDots = dots.map(d => folds[0].apply(d));
+
+    return new Set(foldedDots.map(d => d.key())).size;
+  }
+
+
+  part2(input: string[]): number | string {
+
+    const {dots, folds} = this.parseInput(input);
+
+    let foldedDots = [...dots];
+    for (const fold of folds) {
+
+      foldedDots = foldedDots.map(d => fold.apply(d));
+
+    }
+
+    return this.renderDots(dots);
+  }
+
+
+  private parseInput(input: string[]): { dots: Vector2[], folds: Fold[] } {
+    const dots = input.filter(s => s.trim() !== "" && !s.startsWith("fold"))
+      .map(s => Vector2.parse(s));
+
+    const folds = input.filter(s => s.startsWith("fold"))
+      .map(s => Fold.parseInstruction(s));
+    return {dots, folds};
+  }
+
+  renderDots(dots: Vector2[]): string {
+
+    const minX = Math.min(...dots.map(d => d.x));
+    const maxX = Math.max(...dots.map(d => d.x));
+    const minY = Math.min(...dots.map(d => d.y));
+    const maxY = Math.max(...dots.map(d => d.y));
+
+    const lines = [];
+    for (let y = minY; y <= maxY; y++) {
+      let line = "";
+      for (let x = minX; x <= maxX; x++) {
+        line += dots.some(d => d.x === x && d.y === y) ? "#" : ".";
+      }
+      lines.push(line);
+    }
+    return lines.join("\n");
+  }
+}
+
+class Fold {
+  axis: "x" | "y";
+  foldPosition: number;
+
+  constructor(axis: "x" | "y", position: number) {
+    this.axis = axis;
+    this.foldPosition = position;
+  }
+
+  static parseInstruction(line: string): Fold {
+    if (line.startsWith("fold along y=")) {
+      return new Fold("y", parseInt(line.substr(13)));
+    } else if (line.startsWith("fold along x=")) {
+      return new Fold("x", parseInt(line.substr(13)));
+    } else {
+      throw Error(`Invalid fold instruction: "${line}"`);
+    }
+  }
+
+  apply(pos: Vector2) {
+
+    if (this.axis === "y") {
+
+      return new Vector2(pos.x, this.foldAlong(pos.y));
+    } else {
+
+      return new Vector2(this.foldAlong(pos.x), pos.y);
+    }
+  }
+
+  private foldAlong(pos: number): number {
+
+    if (pos < this.foldPosition) return pos;
+    if (pos === this.foldPosition) console.log("Excuse me WTF?");
+
+    const distanceToFold = pos - this.foldPosition - 1;
+    return this.foldPosition - distanceToFold - 1;
+
+  }
+}
+
+export default Day13;

functions/src/index.ts

@@ -14,6 +14,7 @@ import Day9 from "./day9";
 import Day10 from "./day10";
 import Day11 from "./day11";
 import Day12 from "./day12";
+import Day13 from "./day13";
 
 
 // // Start writing Firebase Functions
@@ -42,6 +43,7 @@ export const day = {
   10: functions.region("europe-west1").https.onRequest((request, response) => { processDay(new Day10(), request, response) }),
   11: functions.region("europe-west1").https.onRequest((request, response) => { processDay(new Day11(), request, response) }),
   12: functions.region("europe-west1").https.onRequest((request, response) => { processDay(new Day12(), request, response) }),
+  13: functions.region("europe-west1").https.onRequest((request, response) => { processDay(new Day13(), request, response) }),
 
 }
 

input/day/13-example.http

@@ -0,0 +1,26 @@
+POST http://localhost:5001/advent-of-code-2021-911a8/europe-west1/day-13
+Content-Type: text/plain
+
+6,10
+0,14
+9,10
+0,3
+10,4
+4,11
+6,0
+6,12
+4,1
+0,13
+10,12
+3,4
+3,0
+8,4
+1,10
+2,14
+8,10
+9,0
+
+fold along y=7
+fold along x=5
+
+###