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breadadamsbreadadams
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15/2024
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‎2024/15/example.txt

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##########
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#..O..O.O#
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#......O.#
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#.OO..O.O#
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#[email protected].#
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#O#..O...#
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#O..O..O.#
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#.OO.O.OO#
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#....O...#
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##########
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<vv>^<v^>v>^vv^v>v<>v^v<v<^vv<<<^><<><>>v<vvv<>^v^>^<<<><<v<<<v^vv^v>^
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vvv<<^>^v^^><<>>><>^<<><^vv^^<>vvv<>><^^v>^>vv<>v<<<<v<^v>^<^^>>>^<v<v
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><>vv>v^v^<>><>>>><^^>vv>v<^^^>>v^v^<^^>v^^>v^<^v>v<>>v^v^<v>v^^<^^vv<
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<<v<^>>^^^^>>>v^<>vvv^><v<<<>^^^vv^<vvv>^>v<^^^^v<>^>vvvv><>>v^<<^^^^^
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^><^><>>><>^^<<^^v>>><^<v>^<vv>>v>>>^v><>^v><<<<v>>v<v<v>vvv>^<><<>^><
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^>><>^v<><^vvv<^^<><v<<<<<><^v<<<><<<^^<v<^^^><^>>^<v^><<<^>>^v<v^v<v^
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>^>>^v>vv>^<<^v<>><<><<v<<v><>v<^vv<<<>^^v^>^^>>><<^v>>v^v><^^>>^<>vv^
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<><^^>^^^<><vvvvv^v<v<<>^v<v>v<<^><<><<><<<^^<<<^<<>><<><^^^>^^<>^>v<>
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^^>vv<^v^v<vv>^<><v<^v>^^^>>>^^vvv^>vvv<>>>^<^>>>>>^<<^v>^vvv<>^<><<v>
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v^^>>><<^^<>>^v^<v^vv<>v^<<>^<^v^v><^<<<><<^<v><v<>vv>>v><v^<vv<>v^<<^

‎2024/15/index.test.ts

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import { expect, describe, test } from "bun:test";
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import { part1, part2 } from ".";
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import { getInputs } from "../../utils/get-inputs";
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const { exampleInput, puzzleInput } = await getInputs("2024/15");
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describe("part 1", () => {
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test("example", () => {
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expect(part1(exampleInput)).toBe(10092);
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});
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test("puzzle", () => {
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expect(part1(puzzleInput)).toBe(1563092);
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});
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});
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describe("part 2", () => {
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test("example", () => {
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expect(part2(exampleInput)).toBe(9021);
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});
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test("puzzle", () => {
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expect(part2(puzzleInput)).toBe(1582688);
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});
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});

‎2024/15/index.ts

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import { timePart1, timePart2 } from "../../utils/time-part";
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const parseInput = (input: string) => {
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const [rawMap, rawMovements] = input.split("\n\n");
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const map = rawMap.split("\n").map((row) => row.split(""));
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const movements = rawMovements.split("\n").join("").split("");
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return { map, movements };
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};
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type InputMap = ReturnType<typeof parseInput>["map"];
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type Coordinate = { x: number; y: number };
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const getInitialPosition = (map: InputMap) => {
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const y = map.findIndex((row) => row.includes("@"));
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const x = map[y].indexOf("@");
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return { x, y };
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};
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const movementDirections = {
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"<": { x: -1, y: 0 },
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"^": { x: 0, y: -1 },
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">": { x: 1, y: 0 },
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v: { x: 0, y: 1 },
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};
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const move = (position: Coordinate, direction: Coordinate) => {
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return {
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x: position.x + direction.x,
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y: position.y + direction.y,
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};
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};
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const readCell = ({ x, y }: Coordinate, map: InputMap) => {
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return map[y][x];
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};
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const findNextEmptyCell = ({
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boxCells = ["O"],
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currentPosition,
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direction,
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map,
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}: {
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boxCells?: string[];
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currentPosition: Coordinate;
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direction: Coordinate;
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map: InputMap;
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}) => {
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let position = currentPosition;
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let i = 0;
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while (true) {
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const nextPos = move(position, direction);
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const cell = readCell(nextPos, map);
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if (cell === ".") {
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position = nextPos;
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break;
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}
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if (boxCells.includes(cell)) {
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position = nextPos;
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i++;
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continue;
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}
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if (cell === "#") {
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i = 0;
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position = currentPosition;
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break;
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}
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}
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return {
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movementCount: i,
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emptyCellPosition: position,
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};
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};
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// const buildMapForPrint = (map: InputMap, currentPosition?: Coordinate) => {
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// const innerMap = JSON.parse(JSON.stringify(map)) as ReturnType<
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// typeof parseInput
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// >["map"];
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// if (currentPosition) {
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// innerMap[currentPosition.y][currentPosition.x] = "@";
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// }
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// return innerMap.map((row) => row.join("")).join("\n");
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// };
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// const printMap = (map: InputMap, currentPosition?: Coordinate) => {
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// console.log(buildMapForPrint(map, currentPosition));
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// };
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const getGPSCoordinateSum = (map: InputMap, matchingChar: string) => {
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let gpsCoordSum = 0;
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for (let y = 0; y < map.length; y++) {
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for (let x = 0; x < map[0].length; x++) {
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const cell = readCell({ x, y }, map);
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if (cell === matchingChar) {
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gpsCoordSum += 100 * y + x;
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}
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}
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}
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return gpsCoordSum;
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};
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export const part1 = timePart1((input: string) => {
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const { map, movements } = parseInput(input);
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let currentPosition = getInitialPosition(map);
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map[currentPosition.y][currentPosition.x] = ".";
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for (const movement of movements) {
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const direction =
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movementDirections[movement as keyof typeof movementDirections];
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const nextPosition = {
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x: currentPosition.x + direction.x,
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y: currentPosition.y + direction.y,
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};
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const cell = readCell(nextPosition, map);
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if (cell === "#") {
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continue;
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}
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if (cell === ".") {
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currentPosition = nextPosition;
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continue;
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}
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if (cell === "O") {
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const nextEmptyCell = findNextEmptyCell({
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currentPosition,
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direction,
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map,
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});
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if (nextEmptyCell.movementCount === 0) {
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continue;
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}
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currentPosition = nextPosition;
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map[currentPosition.y][currentPosition.x] = ".";
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for (let j = 1; j <= nextEmptyCell.movementCount; j++) {
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const blockPushPos = {
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x: currentPosition.x + direction.x * j,
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y: currentPosition.y + direction.y * j,
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};
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map[blockPushPos.y][blockPushPos.x] = "O";
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}
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}
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}
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return getGPSCoordinateSum(map, "O");
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});
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const expandMap = (input: string) => {
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const [map, movements] = input.split("\n\n");
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const expandedMap = map
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.replaceAll("#", "##")
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.replaceAll("O", "[]")
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.replaceAll(".", "..")
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.replaceAll("@", "@.");
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return `${expandedMap}\n\n${movements}`;
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};
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const positionToKey = (position: Coordinate) => `${position.x},${position.y}`;
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const moveBoxesVertically = ({
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// debug,
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direction,
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map,
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initialPosition,
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}: {
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// debug?: boolean;
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direction: Coordinate;
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map: InputMap;
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initialPosition: Coordinate;
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}) => {
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const visited = new Set<string>();
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let toMove: Coordinate[] = [];
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const queue = [initialPosition];
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while (queue.length) {
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const position = queue.pop()!;
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const key = positionToKey(position);
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if (visited.has(key)) {
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continue;
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}
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const cell = readCell(position, map);
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// We hit a wall
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if (cell === "#") {
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toMove = [];
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break;
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}
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// We're on a "]" char
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if (cell === "[") {
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toMove.push(position);
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queue.push({ ...position, x: position.x + 1 });
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queue.push(move(position, direction));
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}
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// We're on a "[" char
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if (cell === "]") {
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toMove.push(position);
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queue.push({ ...position, x: position.x - 1 });
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queue.push(move(position, direction));
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}
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visited.add(key);
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}
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const sortedToMove = toMove.toSorted((a, b) => {
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if (direction.y === 1) {
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return b.y - a.y || b.x - a.x;
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}
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return a.y - b.y || a.x - b.x;
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});
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for (const pos of sortedToMove) {
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const withMove = move(pos, direction);
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const cell = readCell(pos, map);
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map[withMove.y][withMove.x] = cell;
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map[pos.y][pos.x] = ".";
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}
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return { hasMoved: toMove.length };
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};
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export const part2 = timePart2((input: string) => {
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const inputWithExpandedMap = expandMap(input);
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const { map, movements } = parseInput(inputWithExpandedMap);
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let currentPosition = getInitialPosition(map);
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map[currentPosition.y][currentPosition.x] = ".";
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let i = 0;
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for (const movement of movements) {
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i++;
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const direction =
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movementDirections[movement as keyof typeof movementDirections];
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const nextPosition = {
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x: currentPosition.x + direction.x,
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y: currentPosition.y + direction.y,
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};
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const cell = readCell(nextPosition, map);
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if (cell === "#") {
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continue;
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}
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if (cell === ".") {
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currentPosition = nextPosition;
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continue;
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}
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if (cell === "[" || cell === "]") {
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if (movement === "<" || movement === ">") {
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const nextEmptyCell = findNextEmptyCell({
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boxCells: ["[", "]"],
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currentPosition,
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direction,
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map,
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});
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if (nextEmptyCell.movementCount === 0) {
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continue;
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}
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currentPosition = nextPosition;
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map[currentPosition.y][currentPosition.x] = ".";
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for (let j = 1; j <= nextEmptyCell.movementCount; j++) {
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const blockPushPos = {
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x: currentPosition.x + direction.x * j,
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y: currentPosition.y + direction.y * j,
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};
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map[blockPushPos.y][blockPushPos.x] =
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j % 2 === 0
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? movement === "<"
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? "["
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: "]"
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: movement === ">"
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? "["
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: "]";
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}
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}
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if (movement === "^" || movement === "v") {
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const withMove = move(currentPosition, direction);
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const { hasMoved } = moveBoxesVertically({
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direction,
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map,
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initialPosition: withMove,
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});
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if (hasMoved) {
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currentPosition = withMove;
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}
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continue;
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}
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}
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}
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return getGPSCoordinateSum(map, "[");
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});

‎README.md

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66

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| Day | Part 1 | Part 2 |
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| :----------------------------------------: | :----: | :----: |
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| [15](https://adventofcode.com/2024/day/15) | ✅ | ✅ |
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| [14](https://adventofcode.com/2024/day/14) | ✅ | ✅ |
1011
| [13](https://adventofcode.com/2024/day/13) | ✅ | ✅ |
1112
| [12](https://adventofcode.com/2024/day/12) | ✅ | ✅ |

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