68 lines
1.6 KiB
JavaScript
68 lines
1.6 KiB
JavaScript
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import fs from "fs";
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/**
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* Main function for Puzzle B
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*
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* @param {string} data - Puzzle input as a single string.
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* @returns {Promise<number>} Manhattan distance of final position to starting position.
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*/
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async function main(data) {
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const orders = data
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.split(/\r?\n/)
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.map((line) => [line[0], parseInt(line.substring(1))]);
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const ship = [0, 0];
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let waypoint = [10, 1];
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for (const order of orders) {
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const radians = (-order[1] * Math.PI) / 180;
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switch (order[0]) {
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case "L":
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waypoint = [
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Math.round(
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waypoint[0] * Math.cos(-radians) - waypoint[1] * Math.sin(-radians)
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),
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Math.round(
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waypoint[0] * Math.sin(-radians) + waypoint[1] * Math.cos(-radians)
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),
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];
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break;
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case "R":
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waypoint = [
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Math.round(
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waypoint[0] * Math.cos(radians) - waypoint[1] * Math.sin(radians)
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),
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Math.round(
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waypoint[0] * Math.sin(radians) + waypoint[1] * Math.cos(radians)
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),
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];
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break;
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case "F":
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ship[0] += order[1] * waypoint[0];
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ship[1] += order[1] * waypoint[1];
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break;
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case "N":
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waypoint[1] += order[1];
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break;
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case "E":
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waypoint[0] += order[1];
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break;
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case "S":
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waypoint[1] -= order[1];
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break;
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case "W":
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waypoint[0] -= order[1];
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break;
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}
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}
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return Math.abs(ship[0]) + Math.abs(ship[1]);
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}
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fs.readFile("input", (err, data) => {
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if (err) throw err;
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main(data.toString()).then(console.log).catch(console.error);
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});
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