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day 13 tidy

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Joshua Seigler 2024-12-13 12:15:58 -05:00
parent b22d060ef6
commit 6106f22c63
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2 changed files with 19 additions and 53 deletions
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4
.aocrunner.json
View file

@ -196,7 +196,7 @@
"attempts": [ "attempts": [
"0" "0"
], ],
"time": 1984.919458 "time": 1.09525
}, },
"part2": { "part2": {
"solved": true, "solved": true,
@ -204,7 +204,7 @@
"attempts": [ "attempts": [
"5923913045842" "5923913045842"
], ],
"time": 6.418125 "time": 0.817542
} }
}, },
{ {

68
src/day13/index.ts
View file

@ -1,64 +1,30 @@
import run from "aocrunner" import run from "aocrunner"
const parseInput = (rawInput: string) =>
rawInput.split("\n\n").map((machine) => { const solve = (rawInput: string, extra = 0) => {
const machines = rawInput.split("\n\n").map((machine) => {
return machine return machine
.split("\n") .split("\n")
.map((l) => Array.from(l.matchAll(/\d+/g)).map(Number)) .map((l) => Array.from(l.matchAll(/\d+/g)).map(Number))
}) })
return machines.reduce((total, machine) => {
const [[adx, ady], [bdx, bdy], [specx, specy]] = machine
const prizex = extra + specx
const prizey = extra + specy
const bPresses = (prizex * ady - prizey * adx) / (bdx * ady - bdy * adx)
const aPresses = (prizey - bPresses * bdy) / ady
if (bPresses % 1 === 0 && aPresses % 1 === 0) {
return total + 3 * aPresses + bPresses
}
return total
}, 0)
}
const part1 = (rawInput: string) => { const part1 = (rawInput: string) => {
const input = parseInput(rawInput) return solve(rawInput)
let spent = 0
for (const machine of input) {
const [[adx, ady], [bdx, bdy], [prizex, prizey]] = machine
let minCost = Number.POSITIVE_INFINITY
const tried = new Set<string>()
const simulate = (
x: number,
y: number,
aPresses: number,
bPresses: number,
) => {
const key = [x, y, aPresses, bPresses].join()
if (tried.has(key)) return
tried.add(key)
if (x > prizex || y > prizey) {
return
}
const cost = aPresses * 3 + bPresses
if (cost >= minCost) {
return
}
if (x === prizex && y === prizey) {
minCost = cost
return
}
simulate(x + adx, y + ady, aPresses + 1, bPresses)
simulate(x + bdx, y + bdy, aPresses, bPresses + 1)
}
simulate(0, 0, 0, 0)
if (minCost < Number.POSITIVE_INFINITY) {
spent += minCost
}
}
return spent
} }
const part2 = (rawInput: string) => { const part2 = (rawInput: string) => {
const input = parseInput(rawInput) return solve(rawInput, 10000000000000)
let spent = 0
for (const machine of input) {
const [[adx, ady], [bdx, bdy], [specx, specy]] = machine
const prizex = 10000000000000 + specx
const prizey = 10000000000000 + specy
const bPresses = (prizex * ady - prizey * adx) / (bdx * ady - bdy * adx)
const aPresses = (prizey - bPresses * bdy) / ady
console.log({ aPresses, bPresses })
if (bPresses % 1 === 0 && aPresses % 1 === 0) {
spent += 3 * aPresses + bPresses
}
}
return spent
} }
run({ run({