mirror of
https://github.com/Baipyrus/AoC-23.git
synced 2024-08-16 23:39:43 +00:00
39 lines
1.1 KiB
JavaScript
39 lines
1.1 KiB
JavaScript
import { readFileSync } from "fs";
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const t0 = performance.now();
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const input = readFileSync("input.txt")
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.toString()
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.split("\n")
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.filter((e) => e.length > 0);
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const instructions = input[0].split("");
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const maps = input.slice(1).map((a) => {
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const [name, pair] = a.split(" = ");
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const mapping = pair.match(/^\(([A-Z]{3}), ([A-Z]{3})\)$/);
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const [_, L, R] = mapping;
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return { name, mapping: { L, R } };
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});
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const cycles = maps
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.filter((e) => e.name.endsWith("A"))
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.map((e) => {
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let count = 0,
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index = 0;
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let current = e;
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while (!current.name.endsWith("Z")) {
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const direction = instructions[index];
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const mapping = current.mapping[direction];
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current = maps.find((a) => a.name === mapping);
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index = (index + 1) % instructions.length;
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count++;
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}
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return { start: e, end: current, length: count };
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});
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const sizes = cycles.map((e) => e.length);
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const gcd = (a, b) => (b == 0 ? a : gcd(b, a % b));
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const lcm = (a, b) => (a / gcd(a, b)) * b;
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const total = sizes.reduce(lcm, 1);
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console.log(total);
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const t1 = performance.now();
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console.log(`Runtime: ${t1 - t0}ms`);
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