Add solution day 6

day_6/example.txt

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+....#.....
+.........#
+..........
+..#.......
+.......#..
+..........
+.#..^.....
+........#.
+#.........
+......#...

day_6/input.txt

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+......................#...#..............#.....................................#...#..............##..............................
+......#.....#................#....#...........#........#......................#...............................#.....#.#.###..#...#
+...#.#.................#........#.................#.........................................................#.....................
+.....................................................................................................#.........#..................
+.............................#.................#...................................#.....#....#........................#....#.....
+..........................#.....................................................................#..#.............#................
+.................#...........................#..........................#..............................#.#..#...................#.
+..#....#....#......................................................................#....#.........................................
+..................................#............#...........#...........................................#.#....#.............#.#...
+...#...##....................................................................................#..........#..................#......
+..................#.....#......#.....#...#.........#..#.............................#....##.............#...............##.#..#...
+......#...............................................................................................................#..........#
+...........#................................#.......#.............#...............#...................................#...........
+............##...........................#........................................................................#...............
+...............................#........#...#.................................#..#.#.............#...........#....................
+........#..........#.#....................................................#........#....#..#.................................#....
+.........#..............#........................#................................................................................
+..................#..........................#.............#..................#.#...........#.....#...............................
+...#...........#.#..........#.....................................................................................................
+..............#.................#.....................................................................#...#......#.....#..........
+..#.....#................................................................................................#.#.....#..........#.....
+#.#..........#...#.............................#...............#..................................................#.#.............
+..........................#..#.............#................................................................................#.....
+...#..............................................................................................#..............#..#.......#.....
+........................................#......#........................................#...................##...........#........
+.............#..............#...........................##...#............#.....#..#..............................................
+..#....#..#...............#........#.................#............................................#........##...............#.....
+................................................#.......#...........##.............................#.##...........................
+............................#..............#..#...........#...#.....#.#...................#.....#.............................#...
+....................#....................................................................................#........................
+.......................................................................................#.......................##..#..............
+#.............................#.............................................................#............................#........
+..............................................................................#.............#...#.........##......................
+...............#..........................#.............#............#...........................................#................
+................#........................#................................#...#............#.............................#........
+..............................................................#.....#..........#.......#........#....#..................#.........
+........................................................#..............................................................#.......#..
+..#........#............#........#...#.....#.......#..............................................................................
+..#..............#.#.....................................#..................................................#....##...............
+............#........................#..........##.................................................................#........#.....
+............#............#.#...............................................#.......#..............................................
+..................#.........................................#............................#......#..................#...........#..
+........................................................#.............##................................#........................#
+.....................#...#......#.......#............#........#..................#...#.#....................................#.....
+...........................................................................................#..............................#....#..
+....#...................#.............#..........#..................................#.............................................
+......................................#...............................................#..#........................................
+.................#..#............................................#.............................................................#.#
+............##...................................................................................#.........................#......
+.........#.................................................#..#........................................#.....#..........#.....#...
+.........#........................................................................................#.#...............#............#
+..........#..#...........#...................#.....#.......#......#....#..#.......................#..........#..........#.........
+......#...................................................#....#..............#....#.........##...#...............................
+.........#........#........................#...........................................................#.......#................#.
+.....................#...............................................#.##.........................................................
+................................................................................#.............#..............#............#.......
+......#..........#............................................#...#....................#...............................#.........#
+......................................#....#.........#..............................................................#...#.........
+.......##...#.#..........................................................#............#...........#........#...................#..
+.....#............................................................................#............................#..................
+....#..................#....#......#......#......................#......................#.......................................#.
+..#..............#..#............#.................................#............#..................#................#.............
+........................................................#....#...................................##.......................#.......
+..........#..................................#....#........#.......#..........................#................#...............#..
+.....................................#.................#..................#...........#...........................................
+.........#..............#...................................................................................#...................#.
+.................##.................................#.......#.......................................................#.........#...
+...........#.................#..........................#...............................#..#...........................#..........
+.....................................#...........................#...................#..............................#..#..........
+.............................#.....#.................................................#.................##...............#.......#.
+............#.........................................................................................................#...........
+..........##.............#...................#.#...........................................#....................................##
+..........#..#...#...............#........#........................................................#.................#............
+....................#......................#....................................................#.#.....................#.........
+.......................................#............#........................##............#....#..#..............................
+..........#..........#.....................................#.................................#.......#............................
+....#.............#...............................................................................................................
+..#..............................................#....#......#........................................#.................#.........
+...#......#.....#..............................#....#....................#......#..................#...................#.......#..
+...............#..#...........................##..................................................................................
+........#..#.....#.........................#.......#.............#..........................................#................#....
+...#......#.............#...............#.............................................................................##..........
+#.................................#.......#.........#.#.#...................................#...#.#...........#..........#........
+#.........#....#...#.........#.#.............................................................#....................................
+........................#.#.......#.................................................#.............................................
+...#...##...#..#...........................#.....#..........................#...............................#.......#.............
+................#..............................#..........##...................................................................#..
+.......................................................................#...#..#...#.....#....#..................##..........#.....
+#.....................#.........#........#.....................................................................#.....#.......#....
+...........#......................#.......#.................................................#........................#............
+.......#.........................................#.....#...#...........#................#....#......#...........#......#..........
+....#.............#...............................#...#....#..#..#...........................................#.............#......
+...#.........#..........................................#.....#...........^.#...#....#...........................#................
+.....#..#...............#...........................#.#..........#........................................................#.......
+.............#.......#.............................................................................................#...#..........
+..#...................#...............................#......#............#...........#.......#...................................
+...........#.......................#..........#...#.......................#..............#.............##.............#..#........
+..#............#.............#.......................................................#.....##....................................#
+.#.........#.....................................................................#.........#......................................
+.............#....................................................................#.....#.............#...#...........#..........#
+..........................#.....#...#......................#.................................#.....#.................#.......#....
+..........#.#.....................................................................................................................
+............#.......#....................#.......#.............................................#..................................
+.......................................#..#........#...................................................#..........................
+...................#........#....#........#..................#..........................................................#.........
+........#..............#....................#............#......#...........#.....#..............................#.........#......
+.......#.....#.................#.#..#..............................................................#.......#..#...........#......#
+.#....................##.....................................................#...#.....#..........................................
+...........#..................#.....#....#............#...............#....#............#.......................#.................
+........#.....................................#......##............#..........................#..........#....................#...
+..........................#...............................................................#.......................................
+......................#..................................#.....................#.............................................#...#
+.........#..............................................................#........##.........#.......#.............................
+....#...#........#...........#....#.............#............#.....#..............................................................
+...........#...............................................................................................#.......#..#...........
+........#..........................#............................#...........#............#.............................#..........
+.......#...........................#...#...............#..#..#...................#.........#......................................
+..#..............................#........#...........#.......................................#...#...............................
+.............#...#.............#.........#...........#.....................................#................#.....................
+.........................#..........................#.................................#...........................................
+..................##.............#........#......#............#........................#.......#......................#....#......
+.....#............................................................................................................................
+.#..................................#.....#.............#...#.............................................#..............#..##..#.
+...............#........................................................#.........#..#..........#.........................#.......
+.............................................#...................#.................#..................#......................#....
+............................#.......................................................................................#.............
+............#...............#....................#....#..........#..#..............................#......#.......#.......##......
+............#.................................................................................#...................................
+........................#...............................................................#......#.......#.......#.......###......#.
+......................................#.#.........................................#.....#.............................#.........#.

day_6/solve_1.ts

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+export async function readMap(path: string) {
+    const text = await Deno.readTextFile(path);
+    return text.split("\n").map((line) => line.trim().split(""));
+}
+export function mapForEach(
+    map: string[][],
+    callback: (x: number, y: number, value: string) => void,
+) {
+    map.forEach((line, y) => {
+        line.forEach((value, x) => {
+            callback(x, y, value);
+        });
+    });
+}
+export function mapFind(
+    map: string[][],
+    callback: (x: number, y: number, value: string) => boolean,
+) {
+    for (let y = 0; y < map.length; y++) {
+        const line = map[y];
+        for (let x = 0; x < line.length; x++) {
+            if (callback(x, y, line[x])) {
+                return { x, y, value: line[x] };
+            }
+        }
+    }
+    return null;
+}
+export function displayMap(map: string[][]) {
+    map.forEach((line) => {
+        console.log(line.join(""));
+    });
+}
+
+export type Dir = "N" | "E" | "S" | "W";
+export type Pos = { x: number; y: number };
+export type Guard = { pos: Pos; direction: Dir };
+
+export function step(pos: Pos, direction: Dir) {
+    const next = { ...pos };
+    switch (direction) {
+        case "N":
+            next.y -= 1;
+            break;
+        case "E":
+            next.x += 1;
+            break;
+        case "S":
+            next.y += 1;
+            break;
+        case "W":
+            next.x -= 1;
+            break;
+    }
+    return next;
+}
+export function rotateLeft(direction: Dir) {
+    switch (direction) {
+        case "N":
+            return "W";
+        case "E":
+            return "N";
+        case "S":
+            return "E";
+        case "W":
+            return "S";
+    }
+}
+export function rotateRight(direction: Dir) {
+    switch (direction) {
+        case "N":
+            return "E";
+        case "E":
+            return "S";
+        case "S":
+            return "W";
+        case "W":
+            return "N";
+    }
+}
+
+export const EMPTY = ".";
+export const WALL = "#";
+const G = "X";
+
+export function moveGuard(guard: Guard, map: string[][]): Guard | "out" {
+    const { direction } = guard;
+    const next = step(guard.pos, direction);
+    // Check if next position is out of bounds
+    if (
+        next.y < 0 ||
+        next.y >= map.length ||
+        next.x < 0 ||
+        next.x >= map[next.y].length
+    ) {
+        // Out of bounds
+        return "out";
+    }
+    // Check if next position is a wall
+    if (map[next.y][next.x] === WALL) {
+        // Turn right
+        const right = rotateRight(direction);
+        return { ...guard, direction: right };
+    }
+    return { ...guard, pos: next };
+}
+
+
+
+if (import.meta.main) {
+    const map = await readMap("input.txt");
+    const guardPos = mapFind(map, (_x, _y, value) => value === "^");
+    if (!guardPos) {
+        throw new Error("Guard not found");
+    }
+    const { x, y } = guardPos;
+    let guard: Guard = {
+        pos: { x, y },
+        direction: "N",
+    };
+    map[y][x] = G;
+
+    for (;;) {
+        const n = moveGuard(guard, map);
+        if (n === "out") {
+            break;
+        }
+        guard = n;
+        map[guard.pos.y][guard.pos.x] = G;
+    }
+    displayMap(map);
+    let count = 0;
+    mapForEach(map, (_x, _y, value) => {
+        if (value === G) {
+            count++;
+        }
+    });
+    console.log(count);
+}

day_6/solve_2.ts

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+import { readMap, mapFind, Guard, moveGuard, displayMap, mapForEach, Dir, EMPTY, Pos } from "./solve_1.ts";
+
+function getMDir(
+    dir: Dir,
+    mapValue: string
+){
+    if (mapValue === "+") {
+        return mapValue;
+    }
+    if (dir === mapValue || mapValue === EMPTY){
+        return dir;
+    }
+    return "+";
+}
+
+function loopDetect(
+    obstaclePos: Pos,
+    guard: Guard,
+    map: string[][]
+){
+    map[obstaclePos.y][obstaclePos.x] = "#";
+    try {
+        let doubleMoveGaurd: Guard | "out" = guard;
+        for(;;){
+            const n = moveGuard(guard, map);
+            if (n === "out"){
+                return false;
+            }
+            guard = n;
+            doubleMoveGaurd = moveGuard(doubleMoveGaurd, map);
+            if (doubleMoveGaurd === "out"){
+                return false;
+            }
+            doubleMoveGaurd = moveGuard(doubleMoveGaurd, map);
+            if (doubleMoveGaurd === "out"){
+                return false;
+            }
+            if (guard.pos.x === doubleMoveGaurd.pos.x && guard.pos.y === doubleMoveGaurd.pos.y
+                && guard.direction === doubleMoveGaurd.direction
+            ){
+                return true;
+            }
+        }
+    }
+    finally {
+        map[obstaclePos.y][obstaclePos.x] = ".";
+    }
+}
+
+if (import.meta.main) {
+    const map = await readMap("input.txt");
+    const guardPos = mapFind(map, (_x, _y, value) => value === "^");
+    if (!guardPos) {
+        throw new Error("Guard not found");
+    }
+    const { x, y } = guardPos;
+    let guard: Guard = {
+        pos: { x, y },
+        direction: "N",
+    };
+    map[y][x] = "|"
+
+    let count = 0;
+    for (;;) {
+        const n = moveGuard(guard, map);
+        if (n === "out") {
+            break;
+        }
+        if (map[n.pos.y][n.pos.x] === EMPTY){
+            if (loopDetect(n.pos, guard, map)){
+                console.log(n.pos);
+                count++;
+            }
+        }
+        guard = n;
+        const v = map[guard.pos.y][guard.pos.x];
+        map[guard.pos.y][guard.pos.x] = getMDir(guard.direction, v);
+    }
+    displayMap(map);
+    console.log(count);
+}