139 lines
No EOL
3.2 KiB
TypeScript
139 lines
No EOL
3.2 KiB
TypeScript
export async function readMap(path: string) {
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const text = await Deno.readTextFile(path);
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return text.split("\n").map((line) => line.trim().split(""));
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}
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export function mapForEach(
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map: string[][],
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callback: (x: number, y: number, value: string) => void,
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) {
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map.forEach((line, y) => {
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line.forEach((value, x) => {
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callback(x, y, value);
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});
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});
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}
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export function mapFind(
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map: string[][],
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callback: (x: number, y: number, value: string) => boolean,
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) {
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for (let y = 0; y < map.length; y++) {
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const line = map[y];
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for (let x = 0; x < line.length; x++) {
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if (callback(x, y, line[x])) {
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return { x, y, value: line[x] };
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}
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}
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}
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return null;
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}
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export function displayMap(map: string[][]) {
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map.forEach((line) => {
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console.log(line.join(""));
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});
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}
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export type Dir = "N" | "E" | "S" | "W";
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export type Pos = { x: number; y: number };
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export type Guard = { pos: Pos; direction: Dir };
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export function step(pos: Pos, direction: Dir) {
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const next = { ...pos };
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switch (direction) {
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case "N":
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next.y -= 1;
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break;
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case "E":
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next.x += 1;
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break;
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case "S":
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next.y += 1;
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break;
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case "W":
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next.x -= 1;
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break;
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}
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return next;
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}
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export function rotateLeft(direction: Dir) {
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switch (direction) {
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case "N":
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return "W";
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case "E":
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return "N";
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case "S":
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return "E";
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case "W":
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return "S";
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}
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}
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export function rotateRight(direction: Dir) {
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switch (direction) {
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case "N":
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return "E";
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case "E":
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return "S";
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case "S":
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return "W";
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case "W":
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return "N";
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}
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}
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export const EMPTY = ".";
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export const WALL = "#";
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const G = "X";
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export function moveGuard(guard: Guard, map: string[][]): Guard | "out" {
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const { direction } = guard;
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const next = step(guard.pos, direction);
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// Check if next position is out of bounds
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if (
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next.y < 0 ||
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next.y >= map.length ||
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next.x < 0 ||
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next.x >= map[next.y].length
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) {
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// Out of bounds
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return "out";
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}
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// Check if next position is a wall
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if (map[next.y][next.x] === WALL) {
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// Turn right
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const right = rotateRight(direction);
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return { ...guard, direction: right };
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}
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return { ...guard, pos: next };
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}
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if (import.meta.main) {
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const map = await readMap("input.txt");
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const guardPos = mapFind(map, (_x, _y, value) => value === "^");
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if (!guardPos) {
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throw new Error("Guard not found");
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}
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const { x, y } = guardPos;
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let guard: Guard = {
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pos: { x, y },
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direction: "N",
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};
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map[y][x] = G;
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for (;;) {
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const n = moveGuard(guard, map);
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if (n === "out") {
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break;
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}
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guard = n;
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map[guard.pos.y][guard.pos.x] = G;
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}
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displayMap(map);
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let count = 0;
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mapForEach(map, (_x, _y, value) => {
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if (value === G) {
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count++;
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}
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});
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console.log(count);
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} |