90 lines
3.5 KiB
TypeScript
90 lines
3.5 KiB
TypeScript
import { takeWhile } from 'lodash';
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import fs from "fs";
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import {matchAllAndThen} from "./utils";
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export class Engine {
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constructor(private readonly parts: number[][], private readonly schematic: string[][]) {
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}
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public static create(input: string, gearsOnly: boolean = false): Engine {
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const lines = input.split('\n').filter(Boolean);
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const partRegex = /\d+/g;
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const symbolRegex = gearsOnly ? /\*/g : /[^a-zA-Z\d\.]/g;
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const parts : number[][] = new Array(lines.length).fill(0).map(() => new Array(lines[0].length));
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const symbols: string[][] = new Array(lines.length).fill(0).map(() => new Array(lines[0].length));
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lines.forEach((line, lineNumber) => {
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matchAllAndThen(line, partRegex, (match, index) => {
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const parsedNumber = parseInt(match, 10);
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for (let i = index; i < index + match.length; i++) {
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parts[lineNumber][i] = parsedNumber;
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}
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});
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});
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lines.forEach((line, lineNumber) => {
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matchAllAndThen(line, symbolRegex, (match, index) => symbols[lineNumber][index] = match);
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});
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return new Engine(parts, symbols);
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}
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public sumPartNumbers(): number {
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const partsList = this.schematic.flatMap((row, rowIndex) =>
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row.map((symbol, index) => {
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if (!symbol) return symbol;
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const partIndex = [
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[rowIndex - 1, index - 1],
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[rowIndex - 1, index],
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[rowIndex - 1, index + 1],
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[rowIndex, index - 1],
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[rowIndex, index + 1],
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[rowIndex + 1, index - 1],
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[rowIndex + 1, index],
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[rowIndex + 1, index + 1]
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];
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return Array.from(new Set(partIndex.filter(([rowNum, col]) => rowNum >= 0 && rowNum <= this.schematic.length && index >= 0 && index <= row.length)
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.map(([rowNum, column]) => {
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return this.parts[rowNum][column]
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}).filter(Boolean)))
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.reduce((total, val) => total + val,0);
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})
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) as number[];
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return partsList.reduce((total, partNumber) => total + partNumber, 0);
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}
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public gearRatioSums(): number {
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return this.schematic.flatMap((row, rowIndex) =>
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row
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.map((symbol, index) => {
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const partIndex = [
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[rowIndex - 1, index - 1],
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[rowIndex - 1, index],
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[rowIndex - 1, index + 1],
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[rowIndex, index - 1],
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[rowIndex, index + 1],
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[rowIndex + 1, index - 1],
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[rowIndex + 1, index],
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[rowIndex + 1, index + 1]
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];
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return Array.from(new Set(partIndex.filter(([rowNum, col]) => rowNum >= 0 && rowNum <= this.schematic.length && index >= 0 && index <= row.length)
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.map(([rowNum, column]) => {
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return this.parts[rowNum][column]
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}).filter(Boolean)))
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})
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).filter(list => list.length === 2)
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.reduce((total, [a, b]) => {
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return total + (a * b)
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}, 0);
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}
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}
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export const runDayThree = () => {
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const input = fs.readFileSync('./inputs/day_three_input.txt', 'utf8');
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console.log(Engine.create(input).sumPartNumbers())
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console.log(Engine.create(input, true).gearRatioSums())
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} |