Day Three, Part One. Structure the codebase a little

index.ts

@@ -0,0 +1,3 @@
+import { runDayThree } from "./src/day_three";
+
+runDayThree();

package.json

@@ -4,16 +4,20 @@
   "description": "",
   "main": "index.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "jest"
   },
   "author": "",
   "license": "ISC",
   "devDependencies": {
     "@types/jest": "^29.5.10",
+    "@types/lodash": "^4.14.202",
     "@types/node": "^20.10.1",
     "jest": "^29.7.0",
     "ts-jest": "^29.1.1",
     "ts-node": "^10.9.1",
     "typescript": "^5.3.2"
+  },
+  "dependencies": {
+    "lodash": "^4.17.21"
   }
 }

src/day_three.test.ts

@@ -0,0 +1,23 @@
+import { Engine } from "./day_three";
+
+const schematic = `467..114..
+...*......
+..35..633.
+......#...
+617*......
+.....+.58.
+..592.....
+......755.
+...$.*....
+.664.598..`;
+
+
+// const schematic = `.....+.58.
+// ..592.....`;
+
+describe('Day Three', () => {
+    it('should calculate the sum of all part numbers', () => {
+        const engine = Engine.create(schematic);
+        expect(engine.sumPartNumbers()).toEqual(4361);
+    });
+});

src/day_three.ts

@@ -0,0 +1,75 @@
+import { takeWhile } from 'lodash';
+import fs from "fs";
+import {calculateMinimumCubePowers, calculatePossibleGames, parseGame} from "./day_two";
+
+export class Engine {
+    constructor(private readonly partNumbers: number[]) {
+    }
+
+    public static create(input: string): Engine {
+        const lines = input.split('\n').filter(Boolean);
+        const partRegex = /\d+/g;
+        const symbolRegex = /[^a-zA-Z\d\.]/g;
+
+        const parts : number[][] = new Array(lines.length).fill(0).map(() => new Array(lines[0].length));
+        const symbols: string[][] = new Array(lines.length).fill(0).map(() => new Array(lines[0].length));
+
+        lines.forEach((line, lineNumber) => {
+            const matches = [...line.matchAll(partRegex)];
+            matches.map(match => {
+                if (match && match.index !== undefined) {
+                    const parsedNumber = parseInt(match[0], 10);
+                    for (let i = match.index; i < match.index + match[0].length; i++) {
+                        parts[lineNumber][i] = parsedNumber;
+                    }
+                }
+            });
+        });
+
+        lines.forEach((line, lineNumber) => {
+            const matches = [...line.matchAll(symbolRegex)];
+
+            matches.map(match => {
+               if (match && match.index !== undefined) {
+                    symbols[lineNumber][match.index] = match[0];
+               }
+            });
+        });
+        console.log(symbols.length, parts.length)
+
+        const partsList = symbols.flatMap((row, rowIndex) =>
+            row.map((symbol, index) => {
+               if (!symbol) return symbol;
+
+               const partIndex = [
+                   [rowIndex - 1, index - 1],
+                   [rowIndex - 1, index],
+                   [rowIndex - 1, index + 1],
+                   [rowIndex, index - 1],
+                   [rowIndex, index + 1],
+                   [rowIndex + 1, index - 1],
+                   [rowIndex + 1, index],
+                   [rowIndex + 1, index + 1]
+               ];
+               return Array.from(new Set(partIndex.filter(([rowNum, col]) => rowNum >= 0 && rowNum <= symbols.length && index >= 0 && index <= row.length)
+                   .map(([rowNum, column]) => {
+                       return parts[rowNum][column]
+                   }).filter(Boolean)))
+                   .reduce((total, val) => total + val,0);
+            })
+        )
+
+        return new Engine(partsList as number[]);
+    }
+
+    public sumPartNumbers(): number {
+        return this.partNumbers.reduce((total, partNumber) => total + partNumber, 0);
+    }
+}
+
+export const runDayThree = () => {
+    const input = fs.readFileSync('./inputs/day_three_input.txt', 'utf8');
+    const engine = Engine.create(input)
+
+    console.log(engine.sumPartNumbers());
+}

src/day_two.alternative.test.ts

@@ -0,0 +1,63 @@
+import { Game, calculatePossibleGames, calculateMinimumCubePowers } from "./day_two.alternative";
+
+const partOneInput = `Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green`
+
+describe('Day Two', () => {
+    it('should parse a game', () => {
+        const games = partOneInput.split('\n').map(Game.parse);
+        expect(games).toEqual([
+            new Game(1, [
+                    { blue: 3, green: 0, red: 4 },
+                    { blue: 6, red: 1, green: 2 },
+                    { blue: 0, red: 0, green: 2 } 
+                ]
+            ),
+            new Game(2, [
+                    { blue: 1, green: 2, red: 0 },
+                    { blue: 4, red: 1, green: 3 },
+                    { blue: 1, red: 0, green: 1 } 
+                ]
+            ),
+            new Game(
+                3,
+                [
+                    { blue: 6, green: 8, red: 20 },
+                    { blue: 5, red: 4, green: 13 },
+                    { blue: 0, red: 1, green: 5 } 
+                ]
+            ),
+            new Game(
+                4,
+                [
+                    { blue: 6, green: 1, red: 3 },
+                    { blue: 0, red: 6, green: 3 },
+                    { blue: 15, red: 14, green: 3 } 
+                ]
+            ),
+            new Game(
+                5,
+                [
+                    { blue: 1, green: 3, red: 6 },
+                    { blue: 2, red: 1, green: 2 },
+                ]
+            )
+        ]);
+    });
+
+    it('should calculate which games should only have been possible with the number of cubes', () => {
+        const games = partOneInput.split('\n').map(Game.parse);
+        expect(calculatePossibleGames(games, {
+            blue: 14,
+            red: 12,
+            green: 13
+        })).toEqual(8);
+    });
+    it('should find the minimum cubes in a set and sum the powers of the cubes', () => {
+        const games = partOneInput.split('\n').map(Game.parse);
+        expect(calculateMinimumCubePowers(games)).toEqual(2286);
+    });
+});

src/day_two.alternative.ts

@@ -0,0 +1,54 @@
+import { Cubes } from "./day_two";
+
+export class Game {
+    constructor(
+        public readonly id: number,
+        private readonly rounds: Cubes[]
+    ) {}
+
+    public static parse(input: string): Game {
+        const [gameId, roundsInput] = input.split(':');
+        const id = parseInt(gameId.split(' ')[1], 10);
+        
+        const rounds = roundsInput.split(';').map(round => {
+            return round.trim().split(',').map(cube => cube.trim()).reduce((total, cube) => {
+                const [amount, color] = cube.split(' ');
+                total[color as keyof Cubes] = parseInt(amount, 10);
+                return total;
+            }, {blue: 0, green: 0, red: 0} as Cubes);
+        });
+
+        return new Game(id, rounds);
+    }
+
+    private minimumCubesRequired(): Cubes {
+        return this.rounds.reduce((total, round) => {
+            Object.keys(round).forEach(color => {
+                total[color as keyof Cubes] = Math.max(total[color as keyof Cubes], round[color as keyof Cubes]);
+            });
+            return total;
+        }, {blue: 0, green: 0, red: 0} as Cubes);
+    }
+
+    public calculateMinimumCubePowers(): number {
+        const minimumCubes = this.minimumCubesRequired();
+        return minimumCubes.blue * minimumCubes.green * minimumCubes.red;
+    }
+
+    public isPossible(limits: Cubes): boolean {
+        return this.rounds.every(round => {
+            return Object.keys(round).every(color => {
+                return round[color as keyof Cubes] <= limits[color as keyof Cubes];
+            });
+        });
+    }
+}
+
+export const calculatePossibleGames = (games: Game[], limits: Cubes): number => {
+    const possibleGames = games.filter(game => game.isPossible(limits));
+    return possibleGames.reduce((total, game) => total + game.id, 0);
+}
+
+export const calculateMinimumCubePowers = (games: Game[]): number => {
+    return games.reduce((total, game) => total + game.calculateMinimumCubePowers(), 0);
+}

src/day_two.ts

@@ -65,6 +65,4 @@ export const runDayTwo = () => {
     };
     console.log(calculatePossibleGames(games, limits));
     console.log(calculateMinimumCubePowers(games));
-}
+}
-
-runDayTwo();

yarn.lock

@@ -658,6 +658,11 @@
     expect "^29.0.0"
     pretty-format "^29.0.0"
 
+"@types/lodash@^4.14.202":
+  version "4.14.202"
+  resolved "https://registry.yarnpkg.com/@types/lodash/-/lodash-4.14.202.tgz#f09dbd2fb082d507178b2f2a5c7e74bd72ff98f8"
+  integrity sha512-OvlIYQK9tNneDlS0VN54LLd5uiPCBOp7gS5Z0f1mjoJYBrtStzgmJBxONW3U6OZqdtNzZPmn9BS/7WI7BFFcFQ==
+
 "@types/node@*":
   version "20.10.2"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-20.10.2.tgz#32a5e8228357f57714ad28d52229ab04880c2814"
@@ -1736,6 +1741,11 @@ lodash.memoize@4.x:
   resolved "https://registry.yarnpkg.com/lodash.memoize/-/lodash.memoize-4.1.2.tgz#bcc6c49a42a2840ed997f323eada5ecd182e0bfe"
   integrity sha512-t7j+NzmgnQzTAYXcsHYLgimltOV1MXHtlOWf6GjL9Kj8GK5FInw5JotxvbOs+IvV1/Dzo04/fCGfLVs7aXb4Ag==
 
+lodash@^4.17.21:
+  version "4.17.21"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
+  integrity sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg==
+
 lru-cache@^5.1.1:
   version "5.1.1"
   resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-5.1.1.tgz#1da27e6710271947695daf6848e847f01d84b920"