62 lines
1.6 KiB
TypeScript
62 lines
1.6 KiB
TypeScript
import { JSONSet, Vec2, l2Norm, isDiagAdj } from "@/utils";
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export const main = async (lines: string[]): Promise<number | string> => {
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const knots: Vec2[] = Array(10)
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.fill(null)
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.map(() => ({ x: 0, y: 0 }));
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const visited: JSONSet<Vec2> = new JSONSet();
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visited.add(knots[0]);
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for (const step of lines) {
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const [dir, steps_s] = step.split(" ");
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const steps = parseInt(steps_s);
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for (let i = 0; i < steps; ++i) {
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if (dir === "U") knots[0].y += 1;
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if (dir === "L") knots[0].x -= 1;
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if (dir === "R") knots[0].x += 1;
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if (dir === "D") knots[0].y -= 1;
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for (let knotidx = 1; knotidx < knots.length; knotidx++) {
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const [head, tail] = [knots[knotidx - 1], knots[knotidx]];
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if (!isDiagAdj(head, tail)) {
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if (head.y - tail.y === 0) {
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tail.x += Math.floor((head.x - tail.x) / 2);
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} else if (head.x - tail.x === 0) {
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tail.y += Math.floor((head.y - tail.y) / 2);
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} else {
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tail.x += head.x - tail.x > 0 ? 1 : -1;
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tail.y += head.y - tail.y > 0 ? 1 : -1;
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}
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}
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if (knotidx === knots.length - 1) {
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visited.add(tail);
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}
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}
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}
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}
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return visited.size;
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};
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//
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const isrun = process.argv.length > 1 && process.argv[1] === import.meta.path;
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if (isrun) {
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const file = Bun.file("./problem.txt");
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const text = await file.text();
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const lines = text.split("\n").filter((x) => x && x.length);
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console.log("=== COMPUTATION ===\n");
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const answer = await main(lines);
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console.log("\n=== /COMPUTATION ===\n");
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console.log("=== ANSWER TO P2 ===");
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console.log(answer);
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}
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