AoC2025: day 7 part 1

Author: martapanc

2024-2025/src/2025/day07/day07.test.ts

@@ -0,0 +1,13 @@
+import {part1, part2} from "./day07";
+
+describe('2025 Day 7', () => {
+    test('Part 1', async () => {
+        expect(await part1('testInput1')).toEqual(21);
+        expect(await part1('input')).toEqual(1598);
+    });
+
+    test('Part 2', async () => {
+        // expect(await part2('testInput1')).toEqual(31);
+        // expect(await part2('input')).toEqual(29379307);
+    });
+});

2024-2025/src/2025/day07/day07.ts

@@ -0,0 +1,52 @@
+import path from "node:path";
+import {readInputLineByLine} from "@utils/io";
+import {Cardinal, Coord, Grid, move, readLinesToGrid} from "@utils/grid";
+
+export async function part1(inputFile: string) {
+    return await day7(inputFile, findBeanSplits);
+}
+
+export async function part2(inputFile: string) {
+    return await day7(inputFile);
+}
+
+async function day7(inputFile: string, calcFn?: (grid: Grid, initialPos: Coord) => number) {
+    const inputPath = path.join(__dirname, inputFile);
+    const lines = await readInputLineByLine(inputPath);
+    const { grid, initialPos } = readLinesToGrid(lines, 'S');
+    return calcFn?.(grid, initialPos!);
+}
+
+function findBeanSplits(grid: Grid, initialPos: Coord): number {
+    const visited = new Set<string>();
+    const queue: Coord[] = [move(initialPos, Cardinal.SOUTH)];
+    let splits = 0;
+
+    while (queue.length > 0) {
+        let current = queue.shift()!;
+
+        while (true) {
+            const key = current.serialize();
+            const cellValue = grid.get(key);
+
+            if (cellValue === undefined || visited.has(key)) break;
+
+            visited.add(key);
+
+            if (cellValue === '^') {
+                splits++;
+                const left = move(current, Cardinal.WEST);
+                const right = move(current, Cardinal.EAST);
+                if (grid.has(left.serialize()))
+                    queue.push(left);
+                if (grid.has(right.serialize()))
+                    queue.push(right);
+                break;
+            }
+
+            current = move(current, Cardinal.SOUTH);
+        }
+    }
+
+    return splits;
+}

2024-2025/src/2025/day07/testInput1

@@ -0,0 +1,16 @@
+.......S.......
+...............
+.......^.......
+...............
+......^.^......
+...............
+.....^.^.^.....
+...............
+....^.^...^....
+...............
+...^.^...^.^...
+...............
+..^...^.....^..
+...............
+.^.^.^.^.^...^.
+...............

2024-2025/src/utils/grid.ts

@@ -26,6 +26,30 @@ export interface Coord {
 
 export type Grid = Map<string, string>;
 
+export function getMaxX(grid: Grid): number {
+    let max = Number.NEGATIVE_INFINITY;
+    for (const key of grid.keys()) {
+        const { x } = Coord.deserialize(key);
+        if (x > max) max = x;
+    }
+    if (max === Number.NEGATIVE_INFINITY) {
+        throw new Error('Grid is empty');
+    }
+    return max;
+}
+
+export function getMaxY(grid: Grid): number {
+    let max = Number.NEGATIVE_INFINITY;
+    for (const key of grid.keys()) {
+        const { y } = Coord.deserialize(key);
+        if (y > max) max = y;
+    }
+    if (max === Number.NEGATIVE_INFINITY) {
+        throw new Error('Grid is empty');
+    }
+    return max;
+}
+
 export function readLinesToGrid(lines: string[], initialPosId?: string, endPosId?: string) {
     const grid: Grid = new Map();
     let initialPos: Coord | undefined = undefined;
@@ -192,4 +216,4 @@ export function findCoordsWithinManhattanDistance(source: Coord, distance: numbe
     }
 
     return coordinates;
-}
+}