44 lines
1.6 KiB
JavaScript
44 lines
1.6 KiB
JavaScript
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#!/bin/node
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const fs = require('fs');
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fs.readFile('input.txt', (err, data) => {
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const rules = data.toString()
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.split('\n')
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.filter(rule => rule.length > 0)
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.map(rule => rule.split(" bags contain "))
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.map(rule => [rule[0], rule[1].split(', ')
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.filter(line => !line.endsWith('no other bags.'))
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.map(line => line.replace(/ bags?\.?/, ''))
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.map(line => {
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const firstSpaceIndex = line.indexOf(' ');
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return {
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count: parseInt(line.substring(0, firstSpaceIndex)),
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bagColor: line.substring(firstSpaceIndex + 1),
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};
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})]);
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const ruleMap = {};
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for (const [containerColor, contents] of rules) {
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ruleMap[containerColor] = contents;
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}
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const matchingColors = [];
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let matchingColorsCount;
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do {
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matchingColorsCount = matchingColors.length;
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for (const [containerColor, contents] of rules) {
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if (matchingColors.indexOf(containerColor) < 0 &&
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(contents.find(content => content.bagColor === 'shiny gold' || matchingColors.indexOf(content.bagColor) >= 0))) {
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matchingColors.push(containerColor);
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}
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}
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} while (matchingColorsCount !== matchingColors.length);
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function countBagsInBag(bagColor, bagCount) {
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const contents = ruleMap[bagColor];
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return bagCount + bagCount * contents.reduce((sum, content) => sum + countBagsInBag(content.bagColor, content.count), 0);
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}
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console.log(matchingColors.length, countBagsInBag('shiny gold', 1) - 1);
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});
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