joshua/advent-of-code-2020
1
0
Fork 0
mirror of https://github.com/seigler/advent-of-code-2020 synced 2025-07-27 00:06:09 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Use a map

Browse source
This commit is contained in:
Joshua Seigler 2020-12-07 17:31:14 +00:00
parent 0d10bdffca
commit c42b4fbf8f
1 changed files with 13 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

36
solutions/day7/solution.js
View file

@ -5,34 +5,24 @@ const report = (...messages) => console.log(`[${require(fromHere('../../package.
async function run () { async function run () {
// light red bags contain 1 bright white bag, 2 muted yellow bags. // light red bags contain 1 bright white bag, 2 muted yellow bags.
const input = (await read(fromHere('input.txt'), 'utf8')).trim().split('\n').map( const input = new Map();
(await read(fromHere('input.txt'), 'utf8')).trim().split('\n').forEach(
line => { line => {
const [color, rest] = line.split(' bags contain ') const [color, rest] = line.split(' bags contain ')
let contents let contents
if (rest === 'no other bags.') contents = [] if (rest === 'no other bags.') contents = []
else { else {
contents = rest.slice(0, -1).split(', ').map(i => { contents = rest.split(', ').map(i => {
const [, qty, color] = i.match(/(\d+) (.+) bags?/) const [, qty, color] = i.match(/(\d+) (.+) bags?\.?/)
return { return ({
quantity: 1 * qty, quantity: 1 * qty,
color color
} })
}) })
} }
return { input.set(color, contents)
color,
contents
} }
} )
).reduce((acc, cur) => ({ ...acc, [cur.color]: cur.contents }), {})
/*
{
color
contents: [
{ quantity, color}
]
}
*/
await solveForFirstStar(input) await solveForFirstStar(input)
await solveForSecondStar(input) await solveForSecondStar(input)
@ -40,7 +30,7 @@ async function run () {
async function solveForFirstStar (input) { async function solveForFirstStar (input) {
const outerColors = new Set() const outerColors = new Set()
Object.entries(input).forEach(([color, contents]) => { input.forEach((contents, color) => {
if (contents.some( if (contents.some(
bag => bag.color === 'shiny gold') bag => bag.color === 'shiny gold')
) { ) {
@ -50,8 +40,8 @@ async function solveForFirstStar (input) {
let oldSize let oldSize
while (oldSize !== outerColors.size) { while (oldSize !== outerColors.size) {
oldSize = outerColors.size oldSize = outerColors.size
Object.entries(input).forEach( input.forEach(
([color, contents]) => { (contents, color) => {
if ( if (
!outerColors.has(color) && !outerColors.has(color) &&
contents.some(bag => outerColors.has(bag.color)) contents.some(bag => outerColors.has(bag.color))
@ -67,8 +57,8 @@ async function solveForFirstStar (input) {
} }
function count (input, color) { function count (input, color) {
if (input[color].length === 0) return 1 if (input.get(color).length === 0) return 1
return input[color].reduce((acc, bag) => acc + bag.quantity * count(input, bag.color), 1) return input.get(color).reduce((acc, bag) => acc + bag.quantity * count(input, bag.color), 1)
} }
async function solveForSecondStar (input) { async function solveForSecondStar (input) {