80 lines
2.2 KiB
TypeScript
80 lines
2.2 KiB
TypeScript
import fs from "node:fs";
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import { printTime, now, toNum } from "../util";
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const test = false;
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type coord = { x: bigint; y: bigint };
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const data = fs.readFileSync(
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test ? "./inputs/testinput" : "./inputs/input",
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"utf8"
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);
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let timer = now.instant();
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console.log(
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"part one:",
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data
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.split("\n")
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.slice(0, -1)
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.reduce((machines, curr, index) => {
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// parse this mess
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const machine = Math.floor(index / 4);
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switch (index % 4) {
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case 0:
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machines[machine] = {
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...machines[machine],
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A: { x: BigInt(curr.slice(11, 14)), y: BigInt(curr.slice(17)) },
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};
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break;
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case 1:
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machines[machine] = {
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...machines[machine],
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B: { x: BigInt(curr.slice(11, 14)), y: BigInt(curr.slice(17)) },
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};
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break;
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case 2:
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let coords = curr.slice(9).split(", ");
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machines[machine] = {
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...machines[machine],
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Prize: { x: BigInt(coords[0]), y: BigInt(coords[1].slice(2)) },
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};
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// skip processing the blank line
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}
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return machines;
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}, [] as Array<{ A: coord; B: coord; Prize: coord }>)
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.filter((machine) => {
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// remove machines where it's impossible to reach the prize within 100 presses of each button
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return !(
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machine.A.x * BigInt(100) + machine.B.x * BigInt(100) <
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machine.Prize.x ||
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machine.A.y * BigInt(100) + machine.B.y * BigInt(100) < machine.Prize.y
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);
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})
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.map((m) => {
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//94a/22 - 34a/67 = 8400/22 - 5400/67
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for (let a = BigInt(0); a < 101; a++) {
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if (
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(m.A.x * a) / m.B.x - (m.A.y * a) / m.B.y ==
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m.Prize.x / m.B.x - m.Prize.y / m.B.y
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) {
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// b = 8400/22 - 94(a)/22
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return a * BigInt(3) + m.Prize.x / m.B.x - (m.A.x * a) / m.B.x;
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}
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}
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})
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.reduce((total: bigint, m) => {
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if (m !== undefined) {
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return total + m;
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}
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return total;
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}, BigInt(0)),
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printTime(now.instant().since(timer))
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);
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// timer = now.instant();
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// console.log(
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// "part two:",
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// data.split("\n").slice(0, -1),
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// printTime(now.instant().since(timer))
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// );
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